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.
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!
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.
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 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.
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
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..
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
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!
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.
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.
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?
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. 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
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.
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!
Doesn't matter if you connect them in reverse -- he knows the negative reading is actually positive. And he knows in this car it only has one fuse panel
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 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
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
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.
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)..
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.
thank you for this video! would it be possible that one of those jcase fuses is our culprit for parasitic draw or short, if so how do you test it? thanks again!
Of course the fuse itself cannot cause the drain, but if you are asking whether the drain could be passing through a j-case fuse, it is possible, but not likely. This is because the larger fuses typically are a "main" fuse that protects several "sub-circuits" that each have their own smaller fuse. For example, a 30 amp j-case fuse might feed three circuits that are each protected by 10-amp fuses. If there is a drain in one of these circuits, it would show up in the small fuse.
@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.
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... I've been having a drain problem on my 2012 Camry. How do you keep from activating the car alarm each time you reconnect the battery? I finally disconnected the horns on my Camry to at least not have to listen to them. Is there a better way?
You can use a memory saver when you are disconnecting and the battery. I have a video showing how to do that. Just make sure you remove the memory saver once you have your meter connected (the meter reconnects the battery cable). If the memory saver is left in while you try to measure parasitic drain it will give you bad numbers and mislead you.
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?????
Do the larger almost square fuses (the ones in the right front corner of the video thumbnail) to the right of the relays, also have contacts on top to read voltage to detect a voltage drop?
Rick L - No they don't have contacts on top. But if really needed, in most cases the top plastic cover can be pulled out. Which BTW I don't advise. ;-) Cheers
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.
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!
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
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
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 🇬🇧
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.
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.
To do it this way, you would need a meter with a built-in 10-amp or 20-amp fuse. There are are other, more technical ways to do it, such as with a shunt resistor, but this is really the simplest. You can purchase a decent meter with all the right features for about $35.
Would merely unplugging the hood open/ closed switch connector be an open position? Should you not jump the two contacts together with a short wire / paperclip to simulate a closed/ latched position?
Usually on a door jamb switch, a closed door = open switch. This is also true of this hood switch. Therefore, unplugging the switch would give the ECU the same input as a closed hood or door.
Hi, if my car sits for two weeks & I go to start it I get the clicking & it won't turn over, I did the battery drain test result was 00.44 ma. Took all the fuses & relays out 1 by 1 nothing the multimeter didn't drop the battery is new & i checked the alternator diode test was 635 & 1 charges 14.2 at idle. Cheers: Dom
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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!
Clear voice and precised demonstration very easy to understand. Good job men.
Being an engineer, I can tell you that your videos are simply easy to follow.
Thanks.
Create more videos.
Thanks!
A
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!
Really useful. Especially the tip about not removing the fuses. Thanks.
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! No useless commentary or super-dummy-level instruction like every other video-maker, he just gets right to the point.
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.
You explain everything so well and it’s very easy to follow and understand..
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.
Thank you for documenting this and making it simple to understand !
Love this video!!! Kept it simple and to the point!
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 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.
worked a treat, most helpfully presented, thank you
Great video and great explanation. I wish you went further where you finally would overcome the drain !
Bravo Justin you have made my day so simple and works thank you sir excellent fast and simple no momble jomble crap talk awesome....
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
my Honda Odyssey developed a parasite. This video gave me a lot of info. much appreciated. Keep up the good work!
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..
you have the MOST comprehensive and thuro parisitic drain testing in all of youtube. thankyou sir. subscribed.
I'm glad it is helpful! Thanks.
Great tips, many thanks sandy
Super helpful. Thanks for taking the time to make this video.
hey this is good video, strait to the point and informed, good job
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!
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!
Good advice...I didn't know I could check those types of fuses like that...thanks
Best vid so far. Thanks.
Wow such a detailed amazing video by far the most efficient and reliable 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.
Cantfigurewhyampormv
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.
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
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.
This is an excellent video. That probably all of us have had to dealt with at some point, or even currently (battery drain). Will refer to this video.
Great video not confusing at all, great job Thank You.
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.
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.
What a great video, helped to finally understand how to do this.
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?
Awesome video..Thank you for your time and knowledge.
Fabulous camerawork and commentary. TX a lot!
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.
you are a great teacher, keep making more videos.
Check voltage drop on each battery post to its respective cable as well...
Nice video, and thanks for your time
Superb!!!!! Just sorted my 2 cars. Thanks
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
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.
Great tips - IR thermometer gun works good as well but not on small ma. draws.
by far the best explanation on TH-cam.
Thank you!
Thanks for making this video it absolutely helped! 👍👍
very clear and well done. Thanks. Is there a follow up showing how to fix problems?
Wow. That is very smart. Thanks for the power. Information is power.. one less trip to the mechanic
Thank you sir, following your teaching, I was able to identify the problem, faulty radio circuit.
Very clear instructions a well done helpful clip thanks a million
Nice tip, good for learning tip.....thank you.. well straight forward..
Thank you for the video,, easy and true.
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!
Doesn't matter if you connect them in reverse -- he knows the negative reading is actually positive. And he knows in this car it only has one fuse panel
@@shimmeringreflection true but those of us with ADD won't have it LOL
Subscribed! Thank you man! Really!
Great video great explanation thank you your tips are awesome very grateful that you sharing this with us
Thank you for the tip.
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
great one, thank! from vietnam :D
Hi
Very good video, question is where I can buy the battery shutoff switch? And cost?
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!
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.
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.
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 bro explained so simple nice job
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.
Good Morning Justin Miller take care and have a great day Justin Miller
Thanks 👍 Tutorial great 👍 👍 👌 👏
From Nick Ayivor from London England UK 🇬🇧
Great explanation
Subscribed
Good..clear.. video!
This is such a great video but did you find out where the drain was coming from!? The suspense was killing me! 😂
thank you for this video! would it be possible that one of those jcase fuses is our culprit for parasitic draw or short, if so how do you test it? thanks again!
Of course the fuse itself cannot cause the drain, but if you are asking whether the drain could be passing through a j-case fuse, it is possible, but not likely. This is because the larger fuses typically are a "main" fuse that protects several "sub-circuits" that each have their own smaller fuse. For example, a 30 amp j-case fuse might feed three circuits that are each protected by 10-amp fuses. If there is a drain in one of these circuits, it would show up in the small fuse.
@@JustinMillerAutomotive yes that was what i meant. thanks so much!
thank you amazing explanation
Great video thanks!
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
What kind of leads are you using? Not the alligator clips but the actual leads on you dvom? Look different than the ones on my fluke.
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... I've been having a drain problem on my 2012 Camry. How do you keep from activating the car alarm each time you reconnect the battery? I finally disconnected the horns on my Camry to at least not have to listen to them. Is there a better way?
You can use a memory saver when you are disconnecting and the battery. I have a video showing how to do that. Just make sure you remove the memory saver once you have your meter connected (the meter reconnects the battery cable). If the memory saver is left in while you try to measure parasitic drain it will give you bad numbers and mislead you.
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.
What do all the blue and pink things do the look like a relay of some kind 24 of them thanks ...
Do the larger almost square fuses (the ones in the right front corner of the video thumbnail) to the right of the relays, also have contacts on top to read voltage to detect a voltage drop?
Rick L
- No they don't have contacts on top. But if really needed, in most cases the top plastic cover can be pulled out. Which BTW I don't advise. ;-)
Cheers
Find your videos helpful keep them coming .😁
Thanks for the encouragement!
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!
Good stuff.
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.
thanks for the helpful information
great video
thanks
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!
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
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
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 🇬🇧
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.
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
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.
can any multimeter be used, or does it need to have the built in 10amp fuse, thanks for the video
To do it this way, you would need a meter with a built-in 10-amp or 20-amp fuse. There are are other, more technical ways to do it, such as with a shunt resistor, but this is really the simplest. You can purchase a decent meter with all the right features for about $35.
Would merely unplugging the hood open/ closed switch connector be an open position?
Should you not jump the two contacts together with a short wire / paperclip to simulate a closed/ latched position?
Usually on a door jamb switch, a closed door = open switch. This is also true of this hood switch. Therefore, unplugging the switch would give the ECU the same input as a closed hood or door.
@@JustinMillerAutomotive Right...
Hi, if my car sits for two weeks & I go to start it I get the clicking & it won't turn over, I did the battery drain test result was 00.44 ma. Took all the fuses & relays out 1 by 1 nothing the multimeter didn't drop the battery is new & i checked the alternator diode test was 635 & 1 charges 14.2 at idle. Cheers: Dom