One thing that I would add: Before you hook your DMM into series on the negative side, you should hook a 10 amp (or whatever your meter is rated for) fused jumper wire in place of the DMM. If the fuse blows, you know that there is more current flowing than your meter can handle. It’s a simple step that is quick and easy and will save you a bit of grief when trying to locate the source of the drain.
I've watched 4-5 of these videos on the subject and not a single one of them was anywhere near as good as this one. Well done and thanks for the good description.
Some tips: 1) After you defeat the switches and sensors to allow access to all of the fuse panels, the vehicle will need time to go to sleep. It would be good to know how long to wait before a current reading is actually the proper sleep current or sleep current + a parasitic draw, so if you work on the same make of vehicle it might be helpful to test a "normally" working car to see what the sleep current and sleep timing actually looks like. Also, it is helpful if you ask the customer how the car is left after driving. If it is parked in a garage it may not be locked. A max normal sleep current is most likely 50mA or less although it really depends on the vehicle and accessories. 2) It is easier to use a clamp meter as an initial test, like the B&K Precision Model 316, which has a 1mA resolution on the 10 Amp range. The real challenge to using the 316 clamp meter is to get the jaws around all of the battery feed cable. 3) Once the vehicle is asleep if you disconnect the battery the vehicle will reset and the problem may go away after you insert the DMM. If you want to install a shunt (DMM) into the circuit do so in such a way that you do not break the circuit. DMMs have the disadvantage of having a burden voltage when reading current, and if overloaded may blow a fuse. Some perisitic draw problems actually require a key on to key off sequence to recreate the problem the vehicle may draw more than 10 Amps if you go key on. 4) Parasitic loads are not necessarily static in nature, they may be periodic or have a more complex waveform. If I see my clamp meter reading jumping around I know the parasitic draw current is dynamic. To get a better idea of what is going on I use my Fluke Scopemeter and Fluke current probe, both are battery operated, to understand the current signature. 5) Another issue with doing parasitic draw troubleshooting is usually when the problem shows itself the vehicle will usually not start without a jump. So when it arrives at the shop the battery is almost dead. Charging the battery fully to a point where it can be relied upon to provide enough energy to complete the testing will take time. A quicker option is to put the vehicle on "life support". I use a linear DC power supply with current limit and reverse current blocking diode (much like what is in the old fashion chargers called a rectifier or stud mount diode and heatsink). I can then increase the system voltage from the battery or jump start posts, so I can do my testing without the battery going dead. I can actually put a slight charge on the battery while I do my testing. Much like you may do when reflashing modules in a vehicle. I like the linear DC supply over a DC switcher because it has about 50 times less ripple or noise. 6) Parasitic draw troubleshooting is difficult to teach because the problems are so diverse. So it is helpful to have many different approaches to identifying the cause.
by far the most helpful useful video that actually works! THIS IS THE WAY they brought me a ford f250 with parasitic draw they took it to 2 different shop and could not find anything. thanks to this video step by step i followed and solved the issue. thank you for this awesome video
I like measuring the mV across the back of the fuses instead of removing fuses to see if the Amp draw drops like it says in other videos. In my case I KNOW there is a parasitic draw because I just got a new battery a few days ago and after letting car sit a few days (with everything off and all doors closed) so I won't need to mess around with disconnecting the battery cable to hook up the meter in series, I can just go straight to measuring the voltage across the fuses. Brilliant idea.
Awesome vid....the only thing i would add is if you have a large parasitic draw like in this video I usually start by disconnecting the alternator before going to the fuse box. From past experiences of bad diodes in alternators even if you pull all the fuses the drain remains
Aha! Maybe this is my issue. I have a Honda S2000 which has a parasitic draw of 0.4A that continues even if all the fuses are pulled. Before I test the alternator, do you any other ideas of components that can draw but don't go through fuses?
Thanks for the great vid, i'm a newly qualified level 3 technician and I have a lot to learn still I know but your vids are giving me extra diagnostic procedures to carry out and understanding. Cheers bud!
Excellent video. The way you explain it makes it easy to understand. Before I was confused as to why people were measuring a voltage drop instead of pulling the fuses and measuring amps.
Excellent video, most informed video on this problem. Wish all videos were this articulate. Will try this out, have had this problem with many cars and could never find a good video on parasitic drain. Thank you
I've searched & watched videos on this for about an hour. You were the only one that explained where & how to hook up the circuit tester & with great focused video. TYTYTY
I've just subscribed & rang the notification bell. Your video was my guide in tracking down a parasitic grain on my neighbors vehicle. Thank you. I've searched for a Battery Disconnect switch, however, I was unable to find one with small pins for connecting small alligator clamps to it.
You're right. It all comes back to the guideline that says that a 1-amp drain over a 24-hour period will typically drain a fully charged battery to the point that it won't be able to start the car. So, a .5-amps drain would take 48 hours, a .25 amp drain would take 96 hours (4 days), and so on. Based on this math, a 50mA drain would prevent the car from starting after 20 days of sitting, and a 30mA drain would take 33 days. Not to mention that a battery's life is shortened when it spends any amount of time sitting in an undercharged state. I guess the best rule is that the lower the drain is, the better your life will be!
Good video. One small observation and you fixed this at the end of the video but didn't point it out. When using vice grips, don't connect the meter lead to the handle that releases it. That handle is loose and floats on pins so it may not provide a good connection which could give erroneous readings. It is much better to connect to one of the outside handles or better yet, one of the jaws touching the post. Thanks for the video.
Cody..I am a former electronic tech.. That would have come in handy years ago. I even saw where somebody was using 1 ohm resistor ..dont remember how it was used.. but the voltage was supposed to be current of the fuse. I have not tried it..
great video Justin Miller. I have found that on older cars that have had a remote car starter installed that it is the remote starter box that is drawing current. Seems when they get old they don't shut down or something. Check that the alternator isn't the problem. I'm just working on a semi with 4 -1125 amp batteries that go dead in a week.
AL M --I have an old truck with shaved door handles. The receiver was my drain. The receiver is similar to a remote start keyless entry module. Thanks for the tip!
Thanks a lot! Recently my car drained out battery over night. After watching your video I've found that ABS is draining almost 2 amps. It turned out that ABS fuse and contacts in fuse box has been oxidized. Also last few months ABS light on dashboard popped out a lot. Now I know what was causing that.
Thank you. That was excellent with an absolute minimum of idle chat and all of the details needed to do it right. And ditto to "urdu learner" the next step would be a useful followup video - yeah I realize every fuse leads down a different rabbit hole ... but maybe one of the simpler or most common ones?
Arion Stone - Opinions may vary but based on personal experience. The most common cause for parasitic drain in the electrical system are: 1 - Botched work done on the vehicle, mostly associated with sound/media/entertainment. 2 - Wires and/or connectors damaged during interventions be it for normal maintenance or anything else. Bumping or pulling wires or connectors is a big no no, on ANY electrical system. 3 - Components failure. With in component failure a huge number is associated with dirt/corrosion. My 2 cents. ;-) Cheers
You should have connected red (+) voltmeter connector to ground (-) connector of vehicle and the black (-) voltmeter connector to the negative (-) connector of the battery to avoid getting a negative value reading like you show us. Also you mentioned about the door latch to be closed so that the car thinks it is closed and ECU's go to sleep, but you might need the trunk open as well (if you have a 3rd fuse panel which is in the trunk) and also you need to close the hood latches as well. Thanks and good luck!
Good video but i've been taught at the nissan training center not to completely remove the battery terminal until the dmm is connected in series. This way you dont accidentally kill a intermmitent drain for example a relay
Justin I own a Euro shop and have fought with under dash fuses trying to hold both leads with a single hand and making a good contact across the fuse while watching the meter for years. It's like holding chopsticks and after 40 fuses or so behind a glove box your hand will have cramps and you will be ready to say screw this car. I was looking for a better lead to bridge the fuses in tight spaces and stumbled across a very smart technique from another techs thinking out loud that changed the game. They make things like the calvan amp hound and tweezer type connectors to make it easier to get on both sides of the fuse but under a dash it's still a royal pain. So here it is. Find an empty fuse hole in the block that is live with key off on the power buss side and stick a spade connector in it. Run it to your plus side of your tester. If you can't find this just run the lead to any battery plus connection up to and including the battery +. Now you can test all the fuses in the block with only the negative lead in hand having only to make one connection on the cold side of the fuses. Readings are identical to checking across each individual fuse. There will be a third thing you will see though besides dead zero and a small miliamp reading. When you check a fuse that is not hot with the key on you will usually get some type of a ground through the consumer on the circuit and your meter will read out of range for miliamps. This doesn't matter though because this circuit is not hot with the key off and isn't a suspect in your hunt for the parasitic draw. You can eliminate it. Enjoy!
@@JustinMillerAutomotive One caveat Justin, the further you get from the fuse with your power source you may read higher milliamp readings on fuses with current flowing than if you measured across the fuse but that's ok. I don't use the miliamp conversion charts anyway. The dead ones will always read zero. Once you identify the fuse/fuses of interest you can use more precise pinpoint tests moving forward with the diagnosis. Hope that makes sense.
PRODIGY Justin Miller My teacher Amazing what you know thank you very much for sharing what you know Take care and have a great day PRODIGY Justin Miller From Nick Ayivor from London England UK 🇬🇧
Good video, I also just watched erics. Im actually going crazy with my truck. It can sit for 1-2 weeks and start fine but then the next day it has a dead battery. I have put in a new alternator and battery. Have also had it at 2 different garages. No one can figure it out. Im starting to lose my mind.
Justin, I don't think you can measure current across an un-blown fuse. it's the same as touching your two probes together. You "can" measure current across the fuse socket after you pull the fuse.
We aren't measuring current across the fuses; we are measuring the voltage dropped across the fuse. If there is voltage being dropped, we can know that current is flowing through it.
@TheFatNumpty so what are you lost on if you find the bad circuit you can just pull that fuse for temporary relief depending what that fuse controls youll then start looking at the wiring diagram to that circuit. So say it the fuse for horn was drawing power then youd follow the horn, wiring and everything inbetween and repair that actuall issue. He explains it pretty straight forward.
Thank you for your intuitive information I currently have a situation with my 2016 Ford Explorer it is having a parasitic draw on the PCM power relay I currently check fuses I pulled the 10 amp fuse that looks like the one in your video in the exact same position in the relay finally Powers down just curious if you would have any information on that situation thank you
Always set your meter higher than you expect the current or voltage to be, then you can set it lower if needed. Unless you have an autoranging multi meter you could damage the meter if you set it to low.
That was fantastic, thanks! I just wonder why there would be voltage drop across the fuse. I reckon it's the slight resistance of the fuse acting as a load, as voltage drop can only be measured in loaded circuits (drawing amps). But if the fault is downstream of the fuse would it still show up? If so, I don't comprehend the practice of tracking down the problem spot by moving along the circuit -I thought devices before the fault didn't show v.d. I fear my knowledge of this topic is incomplete -but great stuff, kudos.
That is exactly right. Every conductor - even wires and fuses have a little bit of resistance and drop a little bit of voltage. However, voltage only drops when current is flowing. That is the reason we are looking for a voltage drop - because it indicates flowing current.
@@JustinMillerAutomotive Thanks so much for the response! If I could prevail on you again, Is there a reason why one couldn't set the DVM to amperage and check for current at the fuse? Any thoughts on the fuse buddy?
The biggest reasons that you wouldn't want to use your voltmeter's "amperage" setting is that you would need to remove each fuse one at a time to place the meter leads in series with the circuit. Not only would this be time consuming, as a rule, you do not want to remove fuses because it will disable and/or reset the computers on the vehicle, which could cause a lot of confusion or even turn your problem into an intermittent one. On a modern car with many interconnected computers, it is best to measure the voltage drop across the fuses without disrupting the current flow to anything. I tell people to "be stealthy" so that the car doesn't know you are there!
@@JustinMillerAutomotive Oh I get it, one isn't in-line when they probe the contacts on the back of the fuse -now that I think about it, if they were, they couldn't perform a voltage drop test in the first place. I missed that & you have sharpened my comprehension. Thank you so much for your time & generosity of spirit!
Thank you for your good and comprehensive video. If I may, have two questions to ask you about this video. 1) When you disconnect the negative battery terminal from car, then all electrical should not be functioning. Why should one be concern about the door of the car being closed? Once one of the terminals of the battery is disconnected then there should not be any current passing through wires. Am I correct? 2) Why did you connect the red terminal, the positive terminal of the volt meter to the disconnected ground terminal of the battery? Thank you
Typically, the larger fuses feed multiple smaller fuses, so you can usually find the problem in a smaller fuse, which would actually be closer to the problem. However, if none of the fuses seem to have current flowing through them, yet there is a parasitic drain, then it is time to get more serious. It sometimes means checking current flow through the larger fuses or unfused battery cables.
Great Video, but I have a question about the voltage drop across the fuse. Wouldn't you want to check the fuse using a multimeter with the ground being on the neg cable and then touch each fuse instead of trying to get a voltage drop across the fuse? Aren't you just measuring the drop of voltage across the fuse and not the voltage drop across the circuit?
We actually are trying to measure the voltage drop across the fuse only. The voltage dropped will be in proportion to the current flowing through the fuse. If zero volts are dropped across the fuse, there is no current passing through it.
If you’re measuring current or voltage through a good fuse, you have a poor electrical connection where the fuse plugs in. If you want to measure the actual current on an individual circuit, pull the fuse and hook up your leads like you did at the beginning in series with the load.
Removing the fuse is also likely to reset any computers in the circuit and possibly make an intermittent drain go away. You can measure current indirectly by measuring voltage drop. This uses Ohm's law. It is the same principle as using a shunt resistor to measure current. It is very accurate and non-evasive.
I'm having this problem with my 03 GMC 1500, when I find the parasitic drain, can I just remove the fuse and the problem is solved or is more to that...for example if it the radio fuse causing the drain can i remove the fuse and the parasitic drain problem is gone.. By the way...great video
I have the same question so am going to find parasite , pull it , and test with meter every other hour so the battery can be saved Iwont be stranded.Glade you asked that.
if I heard right you said that if an amp was comming from the batterry it would be drained in 24 hours. Would that be 24 amp hours. Idk. I had no idea. This is really good info. I have about a 50 miliamp draw on my 1999 Ford. Expy. In about 3 days my truck battery is getting very weak. I know that my battery is a bit weak.It could be some of the problem. I was told a a while back that my vehicle was ok as long as I didnt go over 45 or so miliamps in sleep mode for the truck. I have been removing fuses etc. Taking pictures as I go. Extra precaution than just using the owners manual.
A 50mA drain is a little more than we would like to see. However, it shouldn't be enough to cause a good battery to drain in just three days. I suspect that your battery needs to be replaced and you won't notice any more problems (for a while anyway). The higher the drain is, the less time the battery spends fully charged and the shorter the battery's life will be.
@@JustinMillerAutomotive I suspect the battery is a little week..Its about 3 years old. Just bought a disconnect at auto auto for about.$8.00. I think that Harbor Freight sells a easier one to install but it has some draw backs.. QUESTION. Why does my battery start out at 13.5 volts and yet discharge faster. I am fairly ignorant about car batteries.
@@PIANOSTYLE100 Car batteries are just like any battery - take your cell phone or laptop battery, for example. The battery can be fully charged, but it's capacity has diminished. Every time you discharge a battery and recharge a battery, it's capacity is diminished slightly. Lithium ion batteries like those in our phones and computers can be charged and discharged thousands of times, with the capacity changing only slightly each time. Conventional car batteries can only be discharged and recharged about 7-10 times before the capacity is diminished so much that it will barely do its job. A battery is a little bit like a bucket that can be filled with water. Over time, sediment may settle at the bottom of the bucket, which reduces the capacity of the bucket - even though you can still fill it to the top with water!
@@JustinMillerAutomotive Never knew this. Batteries are definitely not my forte. Seriously going to have the battery checked. I probably should remove both positive and neg terminals.
At the very most, the pliers will drop 1 millivolt. Your battery voltage can vary by an entire volt. Even brand new battery cables and multimeter leads will drop voltage. Because the current flow is low, the pliers will not have any measurable affect on your drain or your test results.
I'm assuming the clock will be a draw and we already know this. Should we first ensure the clock is on a dedicated circuit and if so remove that fuse? If the radio is on a shared circuit then we'll need to detirmine the draw the clock needs and test to make sure there's not an excessive draw? Yes, removing the fuse will likely awaken the computer so may need to wait the time required (30 or so minutes?) for the computer to shut down.
The clock and other computers in the car will always draw some current for their keep-alive memory. That is the reason that it is acceptable to have up to 30 milliamps of draw at all times.
That dude is amazing but he goes into college course level detail, explaining WHY everything happens. Sometimes you just want instructions on how to do a simple test. ;)
Yes. It depends on whether the switch is open or closed when the hood is open. In this case (and it is the same with most door jamb switches), a closed hood or closed door causes the switch to open. So, shorting the switch would make the ECU think the hood is open, when we want to cause the opposite to happen - to make it think that the hood is closed.
Great video, going to try to find out why my nissan qashqai is draining the battery through this method, but what do you do after you find a fuse that is draining the battery. do you change it, take out for good, how do you fix this problem, any thoughts?
Ideally, you would be able to find a wiring diagram that tells you what is connected to that fuse. Then, you can begin isolating components in that circuit one at a time. For example, if the radio and auxiliary outlet are both connected to the fuse that has high current flow, you could disconnect the radio and see if the drain goes away. If not, you can disconnect the auxiliary outlet. If neither makes the drain go away, then there is something else connected to the circuit. Sometimes it is an aftermarket device that someone has wired into the vehicle.
hi and thanks for the video it helped a lot , but quick question how do I fix it once I diagnosed the broken fuse? ( I'm not a mechanic btw, so pardon me if I sound ignorant)..
Hi Justin Please help, I am facing a Parasitic Drain on my Elantra, i have 300 mA drain, i used a different technique of pulling fuses, and noticed that the "memory fuse" alone drain 100 mA, alone with some other AC fuses. I checked the items related to each fuse, and made sure all is turned off, but still drain available and it is too high! The funny part sometimes it drains and sometimes it doesn't, so sometimes when i turn on the car in the morning, it starts, and sometimes not, although i make sure everything turned off after switching the car off at night! What would you recommend me to do next?
Old question. But here it goes. Either the system is still live when you test it. Or probabilities point that, sometimes On, sometimes OFF, to a relay malfunction (stuck). It's worth mention that dirty contacts, particularly bad ground connection(s) don't help at all. ;-) Cheers
Very nice..my car 45 ah draw .05 amp on parasitic test when all doors are closed and everything is off. Is this too high since it drains very quickly in just 3 days only?????
What about if you don't have a second multimeter? Do you then just hook the battery back up before you start testing the fuses? Also, with your setup of the multimeter being in series, will that have any effect on the results of the fuse testing?
You are exactly right. You can reconnect the battery and then begin checking for voltage drop across the fuses. The multimeter in series will have no affect on current flow.
@@JustinMillerAutomotive Ok that's what I was thinking. However with the car I am testing there is an alarm that sounds when you reconnect the battery. But it doesn't sound when I have the multimeter in series. I get no reading on the meter. I dont expect you to diagnose through TH-cam comments but I am lost lol
No, you can remove the first meter, but you must reconnect the battery cable. If you happen to own two meters, it is just helpful to be able to see that the drain is still there while checking the fuses.
Great video which I watched with interest. 👍👍👍 I have a question, I have a parasitic drain and have checked BOTH fuse boxes inside and the out side with my second meter and none of the fuse showed anything untoward. But at the battery I was show .76mA 🤬🤬🤬 I tried the method without removing the fuses i.e. with probes on top and there was absolutely nothing, no parasitic drain at yet when I go back to the battery I'm back to .76mA🤬🤬🤬 Do you have any ideas please 🤔🤔🤔 My vehicle is an Audi 1.9Tdi 8P1 2009 plate 🚗🚗🚗
This is a pretty large drain. Also, it is very possible that none of the fuses that you have tested have current passing through them. However, we KNOW that there is a drain. Some circuits are not fused (like the starter) and some may have remote fuses that are not in the fuse block. I have a couple of suggestions for you. If you can find a "power distribution" wiring diagram for your car, it will be very helpful for either of these methods. First, if you have access to a thermal imaging camera, you will likely be able to detect heat in the components that are remaining on. With a .76 amp drain, something will be warm. Start by looking at the fuse and relay boxes, then look around the engine compartment and then under the dash and around the interior of the vehicle. Second, look at the positive battery terminal. How many wires or cables come off the positive battery terminal? You can disconnect them one at a time or use a current probe to see which one has the significant current passing through it. Again, with a drain of that size, you will definitely be able to detect it with a current probe. Once you know which battery cable has the drain, where does it lead to? To the starter? The alternator? To the fuse block? If it is to the fuse block, use the power distribution diagram to see how it branches out from there. One of the wires must have the drain in it. You can continue to use your current probe to narrow down which circuit is the problem. I hope that helps!
@@JustinMillerAutomotive Hi there Justin Many thanks for your suggestions. I read somewhere on TH-cam that a faulty alternator, diode pack regulator etc. can have a drain unfortunately I did not read this before I changed my alternator and at the same time inserted new carbon brushes. I really don't want to go through an alternator change again. Can you suggest a test / s that I can perform on my alternator, I have a digital Multimeter x 2 and a Short & Open Finder Digital Diagnostic Tool, I don't possess a thermal image equipment. I look forward to your response. Kind regards Tony
Not every DIYer has multiple multimeters. I've been using the same one for 30 years, and just replaced it with a newer and more function one. Most of use not have ampClamps, so I feel all presentations should be addressed to either DIYer's or actual automotve techs.
This is the fifth video I've watched now on this subject and by far it was the most helpful and thorough.
I'm glad it was helpful!
One thing that I would add:
Before you hook your DMM into series on the negative side, you should hook a 10 amp (or whatever your meter is rated for) fused jumper wire in place of the DMM. If the fuse blows, you know that there is more current flowing than your meter can handle. It’s a simple step that is quick and easy and will save you a bit of grief when trying to locate the source of the drain.
great tip!
Being an engineer, I can tell you that your videos are simply easy to follow.
Thanks.
Create more videos.
Thanks!
A
I've watched 4-5 of these videos on the subject and not a single one of them was anywhere near as good as this one. Well done and thanks for the good description.
Some tips:
1) After you defeat the switches and sensors to allow access to all of the fuse panels, the vehicle will need time to go to sleep. It would be good to know how long to wait before a current reading is actually the proper sleep current or sleep current + a parasitic draw, so if you work on the same make of vehicle it might be helpful to test a "normally" working car to see what the sleep current and sleep timing actually looks like. Also, it is helpful if you ask the customer how the car is left after driving. If it is parked in a garage it may not be locked. A max normal sleep current is most likely 50mA or less although it really depends on the vehicle and accessories.
2) It is easier to use a clamp meter as an initial test, like the B&K Precision Model 316, which has a 1mA resolution on the 10 Amp range. The real challenge to using the 316 clamp meter is to get the jaws around all of the battery feed cable.
3) Once the vehicle is asleep if you disconnect the battery the vehicle will reset and the problem may go away after you insert the DMM. If you want to install a shunt (DMM) into the circuit do so in such a way that you do not break the circuit. DMMs have the disadvantage of having a burden voltage when reading current, and if overloaded may blow a fuse. Some perisitic draw problems actually require a key on to key off sequence to recreate the problem the vehicle may draw more than 10 Amps if you go key on.
4) Parasitic loads are not necessarily static in nature, they may be periodic or have a more complex waveform. If I see my clamp meter reading jumping around I know the parasitic draw current is dynamic. To get a better idea of what is going on I use my Fluke Scopemeter and Fluke current probe, both are battery operated, to understand the current signature.
5) Another issue with doing parasitic draw troubleshooting is usually when the problem shows itself the vehicle will usually not start without a jump. So when it arrives at the shop the battery is almost dead. Charging the battery fully to a point where it can be relied upon to provide enough energy to complete the testing will take time. A quicker option is to put the vehicle on "life support". I use a linear DC power supply with current limit and reverse current blocking diode (much like what is in the old fashion chargers called a rectifier or stud mount diode and heatsink). I can then increase the system voltage from the battery or jump start posts, so I can do my testing without the battery going dead. I can actually put a slight charge on the battery while I do my testing. Much like you may do when reflashing modules in a vehicle. I like the linear DC supply over a DC switcher because it has about 50 times less ripple or noise.
6) Parasitic draw troubleshooting is difficult to teach because the problems are so diverse. So it is helpful to have many different approaches to identifying the cause.
by far the most helpful useful video that actually works! THIS IS THE WAY they brought me a ford f250 with
parasitic draw they took it to 2 different shop and could not find anything. thanks to this video step by step i followed
and solved the issue. thank you for this awesome video
Would be awesome if there was a second part to this video showing how you tracked down the draw after figuring out what circuit it was on.
Excellent! No useless commentary or super-dummy-level instruction like every other video-maker, he just gets right to the point.
Really useful. Especially the tip about not removing the fuses. Thanks.
I like measuring the mV across the back of the fuses instead of removing fuses to see if the Amp draw drops like it says in other videos. In my case I KNOW there is a parasitic draw because I just got a new battery a few days ago and after letting car sit a few days (with everything off and all doors closed) so I won't need to mess around with disconnecting the battery cable to hook up the meter in series, I can just go straight to measuring the voltage across the fuses. Brilliant idea.
Cantfigurewhyampormv
Great video and great explanation. I wish you went further where you finally would overcome the drain !
Awesome vid....the only thing i would add is if you have a large parasitic draw like in this video I usually start by disconnecting the alternator before going to the fuse box. From past experiences of bad diodes in alternators even if you pull all the fuses the drain remains
Aha! Maybe this is my issue. I have a Honda S2000 which has a parasitic draw of 0.4A that continues even if all the fuses are pulled. Before I test the alternator, do you any other ideas of components that can draw but don't go through fuses?
Thanks for the great vid, i'm a newly qualified level 3 technician and I have a lot to learn still I know but your vids are giving me extra diagnostic procedures to carry out and understanding. Cheers bud!
Excellent video. The way you explain it makes it easy to understand. Before I was confused as to why people were measuring a voltage drop instead of pulling the fuses and measuring amps.
you have the MOST comprehensive and thuro parisitic drain testing in all of youtube. thankyou sir. subscribed.
I'm glad it is helpful! Thanks.
Excellent video, most informed video on this problem. Wish all videos were this articulate. Will try this out, have had this problem with many cars and could never find a good video on parasitic drain. Thank you
I've searched & watched videos on this for about an hour. You were the only one that explained where & how to hook up the circuit tester & with great focused video. TYTYTY
Thank you. I'm glad it helped!
I've just subscribed & rang the notification bell.
Your video was my guide in tracking down a parasitic grain on my neighbors vehicle. Thank you. I've searched for a Battery Disconnect switch, however, I was unable to find one with small pins for connecting small alligator clamps to it.
Maybe it is not available where you live, but I purchased my disconnect tools on Amazon or Ebay.
I've heard the rule of thumb vary from 30mA to 50mA. It really depends on the spec range of the car. Good vid.
You're right. It all comes back to the guideline that says that a 1-amp drain over a 24-hour period will typically drain a fully charged battery to the point that it won't be able to start the car. So, a .5-amps drain would take 48 hours, a .25 amp drain would take 96 hours (4 days), and so on. Based on this math, a 50mA drain would prevent the car from starting after 20 days of sitting, and a 30mA drain would take 33 days. Not to mention that a battery's life is shortened when it spends any amount of time sitting in an undercharged state. I guess the best rule is that the lower the drain is, the better your life will be!
Good video. One small observation and you fixed this at the end of the video but didn't point it out. When using vice grips, don't connect the meter lead to the handle that releases it. That handle is loose and floats on pins so it may not provide a good connection which could give erroneous readings. It is much better to connect to one of the outside handles or better yet, one of the jaws touching the post. Thanks for the video.
Thank you I learned more from video like this then I do at my work shop. I am going to level 2 this year for automotive technician
Thank you sir, following your teaching, I was able to identify the problem, faulty radio circuit.
Real slick man i woud have never thought to watch volt drop across fuses thanks for posting
May check for blow fuse?
Cody..I am a former electronic tech.. That would have come in handy years ago. I even saw where somebody was using 1 ohm resistor ..dont remember how it was used.. but the voltage was supposed to be current of the fuse. I have not tried it..
Bravo Justin you have made my day so simple and works thank you sir excellent fast and simple no momble jomble crap talk awesome....
Clear voice and precised demonstration very easy to understand. Good job men.
great video Justin Miller. I have found that on older cars that have had a remote car starter installed that it is the remote starter box that is drawing current. Seems when they get old they don't shut down or something. Check that the alternator isn't the problem. I'm just working on a semi with 4 -1125 amp batteries that go dead in a week.
AL M --I have an old truck with shaved door handles. The receiver was my drain. The receiver is similar to a remote start keyless entry module. Thanks for the tip!
Thanks a lot! Recently my car drained out battery over night. After watching your video I've found that ABS is draining almost 2 amps. It turned out that ABS fuse and contacts in fuse box has been oxidized.
Also last few months ABS light on dashboard popped out a lot. Now I know what was causing that.
my Honda Odyssey developed a parasite. This video gave me a lot of info. much appreciated. Keep up the good work!
Thank you for documenting this and making it simple to understand !
Wow such a detailed amazing video by far the most efficient and reliable video
Thank you. That was excellent with an absolute minimum of idle chat and all of the details needed to do it right. And ditto to "urdu learner" the next step would be a useful followup video - yeah I realize every fuse leads down a different rabbit hole ... but maybe one of the simpler or most common ones?
Great suggestion. Thank you!
Arion Stone
- Opinions may vary but based on personal experience. The most common cause for parasitic drain in the electrical system are:
1 - Botched work done on the vehicle, mostly associated with sound/media/entertainment.
2 - Wires and/or connectors damaged during interventions be it for normal maintenance or anything else. Bumping or pulling wires or connectors is a big no no, on ANY electrical system.
3 - Components failure. With in component failure a huge number is associated with dirt/corrosion.
My 2 cents. ;-)
Cheers
You should have connected red (+) voltmeter connector to ground (-) connector of vehicle and the black (-) voltmeter connector to the negative (-) connector of the battery to avoid getting a negative value reading like you show us.
Also you mentioned about the door latch to be closed so that the car thinks it is closed and ECU's go to sleep, but you might need the trunk open as well (if you have a 3rd fuse panel which is in the trunk) and also you need to close the hood latches as well.
Thanks and good luck!
you are a great teacher, keep making more videos.
Excellent video, best I've seen. I sure wish you guys could work on my Ford Escape, no one around here has a clue how to find and fix this problem.
TheJhaley12 Did you ever find the problem, I have a 2009 Ford Escape, hoping it isn’t the Alternator as it is expensive.
You explain everything so well and it’s very easy to follow and understand..
Good video but i've been taught at the nissan training center not to completely remove the battery terminal until the dmm is connected in series. This way you dont accidentally kill a intermmitent drain for example a relay
Good idea!
Love this video!!! Kept it simple and to the point!
Thanks man, you'r plan works, I had the same problem in South Africa
Kool
These guys are great! i no longer rush to our RSA tricky mechanics nowadays.
Fantastic Video and explanation! Thanks.
Check voltage drop on each battery post to its respective cable as well...
Nice video, and thanks for your time
Very clear instructions a well done helpful clip thanks a million
Justin I own a Euro shop and have fought with under dash fuses trying to hold both leads with a single hand and making a good contact across the fuse while watching the meter for years. It's like holding chopsticks and after 40 fuses or so behind a glove box your hand will have cramps and you will be ready to say screw this car. I was looking for a better lead to bridge the fuses in tight spaces and stumbled across a very smart technique from another techs thinking out loud that changed the game. They make things like the calvan amp hound and tweezer type connectors to make it easier to get on both sides of the fuse but under a dash it's still a royal pain. So here it is. Find an empty fuse hole in the block that is live with key off on the power buss side and stick a spade connector in it. Run it to your plus side of your tester. If you can't find this just run the lead to any battery plus connection up to and including the battery +. Now you can test all the fuses in the block with only the negative lead in hand having only to make one connection on the cold side of the fuses. Readings are identical to checking across each individual fuse. There will be a third thing you will see though besides dead zero and a small miliamp reading. When you check a fuse that is not hot with the key on you will usually get some type of a ground through the consumer on the circuit and your meter will read out of range for miliamps. This doesn't matter though because this circuit is not hot with the key off and isn't a suspect in your hunt for the parasitic draw. You can eliminate it. Enjoy!
Great tip! That is a new idea that I have never thought of!
@@JustinMillerAutomotive One caveat Justin, the further you get from the fuse with your power source you may read higher milliamp readings on fuses with current flowing than if you measured across the fuse but that's ok. I don't use the miliamp conversion charts anyway. The dead ones will always read zero. Once you identify the fuse/fuses of interest you can use more precise pinpoint tests moving forward with the diagnosis. Hope that makes sense.
Thanks for making this video it absolutely helped! 👍👍
Great video not confusing at all, great job Thank You.
What a great video, helped to finally understand how to do this.
Fabulous camerawork and commentary. TX a lot!
Great video great explanation thank you your tips are awesome very grateful that you sharing this with us
This is such a great video but did you find out where the drain was coming from!? The suspense was killing me! 😂
Good Morning Justin Miller take care and have a great day Justin Miller
Thanks 👍 Tutorial great 👍 👍 👌 👏
From Nick Ayivor from London England UK 🇬🇧
Thank you for the video,, easy and true.
PRODIGY Justin Miller
My teacher
Amazing what you know thank you very much for sharing what you know
Take care and have a great day
PRODIGY Justin Miller
From Nick Ayivor from London England UK 🇬🇧
Good video, I also just watched erics. Im actually going crazy with my truck. It can sit for 1-2 weeks and start fine but then the next day it has a dead battery. I have put in a new alternator and battery. Have also had it at 2 different garages. No one can figure it out. Im starting to lose my mind.
great video bro explained so simple nice job
by far the best explanation on TH-cam.
Thank you!
Super helpful. Thanks for taking the time to make this video.
Wow. That is very smart. Thanks for the power. Information is power.. one less trip to the mechanic
Justin, I don't think you can measure current across an un-blown fuse. it's the same as touching your two probes together. You "can" measure current across the fuse socket after you pull the fuse.
We aren't measuring current across the fuses; we are measuring the voltage dropped across the fuse. If there is voltage being dropped, we can know that current is flowing through it.
when you found the circuit that was leaking voltage, why didn't you pull the fuse to see if the amp draw dropped?
Good question. When you pull it out the drain should stop...
@@polarlab113 why? I didn’t see the part where he pulled the fuse either, they just skipped right to the part about that shutoff device thing?
When You Pull A Fuse Out It Can Wake Up Other Circuits And Cause The Amperage To Spike Causing You To Record It Incorrectly
@TheFatNumpty so what are you lost on if you find the bad circuit you can just pull that fuse for temporary relief depending what that fuse controls youll then start looking at the wiring diagram to that circuit. So say it the fuse for horn was drawing power then youd follow the horn, wiring and everything inbetween and repair that actuall issue. He explains it pretty straight forward.
@@TheFatNumptyright around 8:40
Thank you for your intuitive information I currently have a situation with my 2016 Ford Explorer it is having a parasitic draw on the PCM power relay I currently check fuses I pulled the 10 amp fuse that looks like the one in your video in the exact same position in the relay finally Powers down just curious if you would have any information on that situation thank you
Good advice...I didn't know I could check those types of fuses like that...thanks
Always set your meter higher than you expect the current or voltage to be, then you can set it lower if needed. Unless you have an autoranging multi meter you could damage the meter if you set it to low.
very clear and well done. Thanks. Is there a follow up showing how to fix problems?
Great explanation
Subscribed
hey this is good video, strait to the point and informed, good job
That was fantastic, thanks! I just wonder why there would be voltage drop across the fuse. I reckon it's the slight resistance of the fuse acting as a load, as voltage drop can only be measured in loaded circuits (drawing amps). But if the fault is downstream of the fuse would it still show up? If so, I don't comprehend the practice of tracking down the problem spot by moving along the circuit -I thought devices before the fault didn't show v.d. I fear my knowledge of this topic is incomplete -but great stuff, kudos.
That is exactly right. Every conductor - even wires and fuses have a little bit of resistance and drop a little bit of voltage. However, voltage only drops when current is flowing. That is the reason we are looking for a voltage drop - because it indicates flowing current.
@@JustinMillerAutomotive Thanks so much for the response! If I could prevail on you again, Is there a reason why one couldn't set the DVM to amperage and check for current at the fuse? Any thoughts on the fuse buddy?
The biggest reasons that you wouldn't want to use your voltmeter's "amperage" setting is that you would need to remove each fuse one at a time to place the meter leads in series with the circuit. Not only would this be time consuming, as a rule, you do not want to remove fuses because it will disable and/or reset the computers on the vehicle, which could cause a lot of confusion or even turn your problem into an intermittent one.
On a modern car with many interconnected computers, it is best to measure the voltage drop across the fuses without disrupting the current flow to anything. I tell people to "be stealthy" so that the car doesn't know you are there!
@@JustinMillerAutomotive Oh I get it, one isn't in-line when they probe the contacts on the back of the fuse -now that I think about it, if they were, they couldn't perform a voltage drop test in the first place. I missed that & you have sharpened my comprehension. Thank you so much for your time & generosity of spirit!
Best vid so far. Thanks.
thank you amazing explanation
Thank you for your good and comprehensive video. If I may, have two questions to ask you about this video.
1) When you disconnect the negative battery terminal from car, then all electrical should not be functioning. Why should one be concern about the door of the car being closed? Once one of the terminals of the battery is disconnected then there should not be any current passing through wires. Am I correct?
2) Why did you connect the red terminal, the positive terminal of the volt meter to the disconnected ground terminal of the battery? Thank you
As soon as you connect the multi-meter in series, you've re-established the circuit and things turn back on.
I can already see what's draining the battery bruh! The multi-colored underbody LED neon light system is still on! It looks so dope too!
very informing video. thanks.
how about the other fuses that you didn`t check, what if one of those causing the drain.
Typically, the larger fuses feed multiple smaller fuses, so you can usually find the problem in a smaller fuse, which would actually be closer to the problem. However, if none of the fuses seem to have current flowing through them, yet there is a parasitic drain, then it is time to get more serious. It sometimes means checking current flow through the larger fuses or unfused battery cables.
Great Video, but I have a question about the voltage drop across the fuse. Wouldn't you want to check the fuse using a multimeter with the ground being on the neg cable and then touch each fuse instead of trying to get a voltage drop across the fuse? Aren't you just measuring the drop of voltage across the fuse and not the voltage drop across the circuit?
We actually are trying to measure the voltage drop across the fuse only. The voltage dropped will be in proportion to the current flowing through the fuse. If zero volts are dropped across the fuse, there is no current passing through it.
If you’re measuring current or voltage through a good fuse, you have a poor electrical connection where the fuse plugs in. If you want to measure the actual current on an individual circuit, pull the fuse and hook up your leads like you did at the beginning in series with the load.
Removing the fuse is also likely to reset any computers in the circuit and possibly make an intermittent drain go away. You can measure current indirectly by measuring voltage drop. This uses Ohm's law. It is the same principle as using a shunt resistor to measure current. It is very accurate and non-evasive.
Great tips - IR thermometer gun works good as well but not on small ma. draws.
Find your videos helpful keep them coming .😁
Thanks for the encouragement!
Superb!!!!! Just sorted my 2 cars. Thanks
worked a treat, most helpfully presented, thank you
I'm having this problem with my 03 GMC 1500, when I find the parasitic drain, can I just remove the fuse and the problem is solved or is more to that...for example if it the radio fuse causing the drain can i remove the fuse and the parasitic drain problem is gone..
By the way...great video
I have the same question so am going to find parasite , pull it , and test with meter every other hour so the battery can be saved Iwont be stranded.Glade you asked that.
If you don't want to use that circuit, sure. You may need that circuit to run the car or gauges. Depends on which fuse you pull
if I heard right you said that if an amp was comming from the batterry it would be drained in 24 hours. Would that be 24 amp hours. Idk. I had no idea. This is really good info. I have about a 50 miliamp draw on
my 1999 Ford. Expy. In about 3 days my truck battery is getting very weak. I know that my battery is a bit weak.It could be some of the problem. I was told a a while back that my vehicle was ok as long as I didnt go over 45 or so miliamps in sleep mode for the truck. I have been removing fuses etc. Taking pictures as I go. Extra precaution than just using the owners manual.
A 50mA drain is a little more than we would like to see. However, it shouldn't be enough to cause a good battery to drain in just three days. I suspect that your battery needs to be replaced and you won't notice any more problems (for a while anyway). The higher the drain is, the less time the battery spends fully charged and the shorter the battery's life will be.
@@JustinMillerAutomotive I suspect the battery is a little week..Its about 3 years old. Just bought a disconnect at auto auto for about.$8.00. I think that Harbor Freight sells a easier one to install but it has some draw backs.. QUESTION. Why does my battery start out at 13.5 volts and yet discharge faster. I am fairly ignorant about car batteries.
@@PIANOSTYLE100 Car batteries are just like any battery - take your cell phone or laptop battery, for example. The battery can be fully charged, but it's capacity has diminished. Every time you discharge a battery and recharge a battery, it's capacity is diminished slightly. Lithium ion batteries like those in our phones and computers can be charged and discharged thousands of times, with the capacity changing only slightly each time. Conventional car batteries can only be discharged and recharged about 7-10 times before the capacity is diminished so much that it will barely do its job.
A battery is a little bit like a bucket that can be filled with water. Over time, sediment may settle at the bottom of the bucket, which reduces the capacity of the bucket - even though you can still fill it to the top with water!
@@JustinMillerAutomotive Never knew this. Batteries are definitely not my forte. Seriously going to have the battery checked. I probably should remove both positive and neg terminals.
Awesome video..Thank you for your time and knowledge.
Great video thanks!
Nice tip, good for learning tip.....thank you.. well straight forward..
that pair of pliers is going to add a resistance, which will effect the readings, pliers are also coated so not going to get a good connection.
At the very most, the pliers will drop 1 millivolt. Your battery voltage can vary by an entire volt. Even brand new battery cables and multimeter leads will drop voltage. Because the current flow is low, the pliers will not have any measurable affect on your drain or your test results.
Thanks battery cutoff switch is useful.
Great tips, many thanks sandy
I'm assuming the clock will be a draw and we already know this. Should we first ensure the clock is on a dedicated circuit and if so remove that fuse? If the radio is on a shared circuit then we'll need to detirmine the draw the clock needs and test to make sure there's not an excessive draw? Yes, removing the fuse will likely awaken the computer so may need to wait the time required (30 or so minutes?) for the computer to shut down.
The clock and other computers in the car will always draw some current for their keep-alive memory. That is the reason that it is acceptable to have up to 30 milliamps of draw at all times.
great one, thank! from vietnam :D
Hi
Way better than the explanation on Shrodinger's Box.
sssshhh !!
you will hurt Bernie's big ego
That dude is amazing but he goes into college course level detail, explaining WHY everything happens. Sometimes you just want instructions on how to do a simple test. ;)
You pulled the pigtail of the hood switch, now put one wire in both pigtail whole to trick the car to think the hood is closed. thanks bill
Yes. It depends on whether the switch is open or closed when the hood is open. In this case (and it is the same with most door jamb switches), a closed hood or closed door causes the switch to open. So, shorting the switch would make the ECU think the hood is open, when we want to cause the opposite to happen - to make it think that the hood is closed.
Great video, going to try to find out why my nissan qashqai is draining the battery through this method, but what do you do after you find a fuse that is draining the battery. do you change it, take out for good, how do you fix this problem, any thoughts?
Ideally, you would be able to find a wiring diagram that tells you what is connected to that fuse. Then, you can begin isolating components in that circuit one at a time. For example, if the radio and auxiliary outlet are both connected to the fuse that has high current flow, you could disconnect the radio and see if the drain goes away. If not, you can disconnect the auxiliary outlet. If neither makes the drain go away, then there is something else connected to the circuit. Sometimes it is an aftermarket device that someone has wired into the vehicle.
hi and thanks for the video it helped a lot , but quick question how do I fix it once I diagnosed the broken fuse? ( I'm not a mechanic btw, so pardon me if I sound ignorant)..
great video, thanks Justin!!.. I"m wondering, what was the problem? What did that Fuse go to?.,.. thanks..
It was a fuse to the interior courtesy lights. I had created this issue intentionally to simulate a parasitic drain by leaving the door switch closed.
Hi Justin Please help, I am facing a Parasitic Drain on my Elantra, i have 300 mA drain, i used a different technique of pulling fuses, and noticed that the "memory fuse" alone drain 100 mA, alone with some other AC fuses. I checked the items related to each fuse, and made sure all is turned off, but still drain available and it is too high! The funny part sometimes it drains and sometimes it doesn't, so sometimes when i turn on the car in the morning, it starts, and sometimes not, although i make sure everything turned off after switching the car off at night! What would you recommend me to do next?
Old question. But here it goes.
Either the system is still live when you test it. Or probabilities point that, sometimes On, sometimes OFF, to a relay malfunction (stuck). It's worth mention that dirty contacts, particularly bad ground connection(s) don't help at all. ;-)
Cheers
Very nice..my car 45 ah draw .05 amp on parasitic test when all doors are closed and everything is off. Is this too high since it drains very quickly in just 3 days only?????
Might be a bit late for this, but a draw of 0.05 amps is a 50 mA draw. 30 mA is considered excessive.
Although this was super cool. I was waiting to see the problem solved.
Me too.
What about if you don't have a second multimeter? Do you then just hook the battery back up before you start testing the fuses? Also, with your setup of the multimeter being in series, will that have any effect on the results of the fuse testing?
You are exactly right. You can reconnect the battery and then begin checking for voltage drop across the fuses. The multimeter in series will have no affect on current flow.
@@JustinMillerAutomotive Ok that's what I was thinking. However with the car I am testing there is an alarm that sounds when you reconnect the battery. But it doesn't sound when I have the multimeter in series. I get no reading on the meter. I dont expect you to diagnose through TH-cam comments but I am lost lol
do you have to have the first multimeter connected to the battery terminal/cable to test the fuses?
No, you can remove the first meter, but you must reconnect the battery cable. If you happen to own two meters, it is just helpful to be able to see that the drain is still there while checking the fuses.
@@JustinMillerAutomotive oh okay thank you for clarifying, great video by the way. very helpful :)
Very good video, question is where I can buy the battery shutoff switch? And cost?
Subscribed! Thank you man! Really!
Great video which I watched with interest. 👍👍👍
I have a question, I have a parasitic drain and have checked BOTH fuse boxes inside and the out side with my second meter and none of the fuse showed anything untoward.
But at the battery I was show .76mA 🤬🤬🤬
I tried the method without removing the fuses i.e. with probes on top and there was absolutely nothing, no parasitic drain at yet when I go back to the battery I'm back to .76mA🤬🤬🤬
Do you have any ideas please 🤔🤔🤔
My vehicle is an Audi 1.9Tdi 8P1 2009 plate 🚗🚗🚗
This is a pretty large drain. Also, it is very possible that none of the fuses that you have tested have current passing through them. However, we KNOW that there is a drain. Some circuits are not fused (like the starter) and some may have remote fuses that are not in the fuse block.
I have a couple of suggestions for you. If you can find a "power distribution" wiring diagram for your car, it will be very helpful for either of these methods.
First, if you have access to a thermal imaging camera, you will likely be able to detect heat in the components that are remaining on. With a .76 amp drain, something will be warm. Start by looking at the fuse and relay boxes, then look around the engine compartment and then under the dash and around the interior of the vehicle.
Second, look at the positive battery terminal. How many wires or cables come off the positive battery terminal? You can disconnect them one at a time or use a current probe to see which one has the significant current passing through it. Again, with a drain of that size, you will definitely be able to detect it with a current probe. Once you know which battery cable has the drain, where does it lead to? To the starter? The alternator? To the fuse block?
If it is to the fuse block, use the power distribution diagram to see how it branches out from there. One of the wires must have the drain in it. You can continue to use your current probe to narrow down which circuit is the problem.
I hope that helps!
@@JustinMillerAutomotive Hi there Justin
Many thanks for your suggestions.
I read somewhere on TH-cam that a faulty alternator, diode pack regulator etc. can have a drain unfortunately I did not read this before I changed my alternator and at the same time inserted new carbon brushes.
I really don't want to go through an alternator change again.
Can you suggest a test / s that I can perform on my alternator, I have a digital Multimeter x 2 and a Short & Open Finder
Digital Diagnostic Tool, I don't possess a thermal image equipment.
I look forward to your response.
Kind regards
Tony
Not every DIYer has multiple multimeters. I've been using the same one for 30 years, and just replaced it with a newer and more function one. Most of use not have ampClamps, so I feel all presentations should be addressed to either DIYer's or actual automotve techs.
The tool he calls Pliers are called Mol - grips.