Clear, simple and no bs. Excellent video! The a/c in my chevy Duramax appeared dead. Jumpered the relay as you directed and found life in the clutch. Added R-134a to the system and got cold air again! Apparently the a/c system is disabled when the refrigerant charge is low. Your video saved me time and money. Thanks!
Hey man thanks for posting this. 2014 Tacoma. AC light on, no clutch engagement. Removed relay, jumped the wires, clutch clicked. Went to Autozone, bought a can of stuff, jumped the wires with full fan and max ac, read 0 psi on the low side. Added enough R134 to get to about 40psi. Reinstalled relay, no engagement. Bought a new relay for $15 and whammo, everything working now. Was quoted $900 to replace my compressor after my "friend" listened to me talk about it and responded in like 2 seconds. Smh. $45 for the can o' stuff. I probably have a leak somewhere. Thanks again!
Sounds like your friend deserves $200 for that brilliant advice he gave you But typically we don’t think like that and rather pay complete strangers/other mechanics $900+
Thanks for this!!! Gone without a/c for a year in our 2011 Ford fusion and a shop wanted $1,800 to “revamp” the entire HVAC system because it would be “easier” to do. Thought my compressor went bad but using your testing method I found that mine is actually still engages. So which leads me to believe my Evap sensor has gone bad. So thank you! You’ve potentially saved me a lot of time and some money.
Great video. Most videos show you how it could go bad and what else to check but nobody was showing how simple it is to check if the ac compressor clutch is engaging.
Hell yea bro this worked for me. Thanks! I bought a truck that was sitting for 5 years and wasn't sure if the compressor was bad or just needed recharged since the compressor wouldn't kick on while ac was turned on. Jumped the two leads and the clutch engaged
@@mikeprice83071 and 5 work too because 1 is continuous 12v and 3 is the 12v that is received once the solenoid in the relay closes. Either way, you’re getting 12v so it works. 3 and 5 is the recommended method, 1 and 5 works just as fine.
Thank you for posting this video. I was able to get the compressor clutch to engage and charged my AC using your instructions on my Cadillac escalade. Now i have to figure out the right PSI for my system.
Thank you for the tips. Allowed me to successfully correct the hot air blowing from my AC. Apparently my compressor didnt have enough refrigerant to kick in - this bypass allowed it to filled. thanks again
Derrick Smiley No as soon as I put the ac refill can on the low side and pulled the trigger ( while the car was running) it automatically turned on both ac fans! There’s a leak in my ac system so when it’s low it shuts down the ac compressor! Just have to get a black light to find the dye!
Great video. Just tested my compressor on my 06 Silverado and it works. Thanks for the info. Now time to find which sensor/switch is bad. Used my horn relay to test the a/c relay before and nothing happened. So I believe I do have a safety switch gone bad and possibly a leak in the system.
That was a great video! I applied this to my 04 Impala LS and the clutch did pull in. I also additionally disconnected the coolant Temp Sensor and started the car to make sure my AC Rad FANS were in working order as the AC fan was not working with the clutch not pulling in. Knowing that the relays and fans were good I went ahead and refilled the refrigerant and BLAMO! Everything is working great! Thanks man! Video helped alot!
This actually turned out helpful. Having a problem with my ac that keeps burning out the compressor fuse and i'm trying to figure out whether it's the clutch, wires or the relay.
@@m0bilemechanix do I'm trying to figure out what I need to do..I'm no mechanic but I did exactly what you did in the video and my ac clutch did the same thing yours did it click on!!? So what do I need to do to fix it
@@m0bilemechanix same with mine. Not enough R-134A to allow the clutch to engage. Worked awesome, and now my wife has a cool car, at least long enough to get to a garage to have the system looked at.
Why is this such a catch 22? Clutch wont engage with low refrigerant yet cant fill refrigerant unless clutch engages... is this how professional mechanics bypass this catch 22?
Well Eric you've done it again saved the day! Improvised tools beating the counter at the parts store once again! If you ever feel like letting me know how to go about replacing the wire that goes to the pressure switch please let me know as it has been discontinued. Thanks your pal Mopar Mike. Since they now own my behind. Lol
@@exiledintheus7251 might not be able to get one but I usually start with AutoZone and then I call the dealership. Tell them you need the pigtail for the pressure switch (witch ever you need high or low) of all else fails some salvage yards will let you cut one off a vehicle
@@m0bilemechanix I know this is old, but I replaced my high pressure switch on my 2007 Saturn Vue thinking it was the reason my AC went out. Before I put the new switch in, I could still hear the compressor turn on but after I replaced the switch the compressor wasn’t making anymore noise. I made sure I had enough refrigerant in the system and no leaks. I’m gonna give this a try later tonight when it “cools down” as it’s already in the triple digits here and I’m dying with no AC. Thanks to TH-cam videos, I never knew a girl like me would be able to learn/do so much work on my own car!
Thanks for the tutorial!! In my case, after doing all this I found the large connector behind the clutch to be a bad contact...Check your connections too folks!
i know im asking randomly but does someone know of a trick to log back into an instagram account? I was dumb forgot my login password. I would love any tricks you can give me
@Case Leonard thanks so much for your reply. I got to the site on google and im trying it out now. Seems to take quite some time so I will get back to you later with my results.
Thanks bud! I did this on my Grand Prix like 5 years ago so I forgot how to do it. My brother in law has a Lincoln which he filled with Free-on but the clutch did not engage so I wanted to test it this way to see if that works at all.
I tried your method and my AC compressor was good, I recharged the system with UV die to find out if it has a leak. The AC blows cold now and I can't see any leaks yet.
@@jdenha7078 so you just had low Freon probably the low pressure switch kept the Ac from running. I’m having the same issue I checked relay even swapped relays around and still nothing fuse not blown and AC diode checked good. The AC button lights up so I’m sure that’s working but the relays not be commanded on so no powers hitting the Ac clutch. Maybe I’m low on Freon
@@ryans413 I actually found the leak using the UV dye. It was coming from the o rings. So now I am out of AC again I guess it's time to change the O-rings and then recharge the system.
Our van, the cluch engagesn and immediately disengages. I'm guessing the relay is bad or the low pressure is just enough to get it to engage then disengage. Hopefully the compressor is still good :)
Why my compressor clutch not engaging when i do this same test on my car relay box,and when I test direct to my battery the compressor clutch is working.whats the problem on this situation?hope you notice me sir thankyou!
After relay u have trinary switch who controls ac compressor if pressure is low or u have leak somewhere because trinary switch compressor will not start. Safe measure Or faulty switch can be problem to
That's an awesome engine bay design .. seems like the alternator is also on top. No need to get under the car or remove the tire. My quest sucks with space. Lol
Question if I connected a jumper wire to the 87 and to the 30 but the compressor did not make any clicking noise is it a bad connection or a bad clutch or a bad compressor?
Very good vidéo, well explained. It worked perfect for me, just cut myself a bit of wire and tried it. Didn't clic that loud for me, but with a video I could see it engaged well. Replaced the relay and solved! Thanks!
Thanks for the tips, very helpful places to start looking. Btw if ur amp power cable is still loose like that, you’ve gotta loom and secure it around the main engine area, ideally similar to OEM wiring paths, and grommet thru the firewall if u can’t find a punch out. Same goes for all cabling. Clean secure adequately sized grounds to chassis/frame are key! Extra bonus points for extra clean wiring cuz u know it’s solid and very easy to work on if needed later. And u certainly should do a big 3 / 4 upgrade or at least the battery ground wire for best results regardless of draw cuz oem wires are cheap and puny.
This is what I was looking for - explained everything! LR Discovery 2 with original factory air - blowing warm air now after 16 years - was hoping it was just the ac compressor clutch/solenoid (it recently stopped engaging). It's a Denso compressor; will do your check as described here and hopefully it is the clutch/solenoid at fault and I can replace myself without having to have the system degassed and spend bug $$$ on a new compressor! The system is fully charged with R134A gas now. Probably also worth replacing the receiver/drier, but I guess that would mean degassing the system as well. Thank you!
Thanks. I just got a quote for $2500 to replace my a/c so i wanna go through and see if i can fix it on my own and this video is a great place to start
got a 2001 GMC Sierra 1500.....my clutch is not engaging at all....got no power with voltage tester to any pressure switches or recirc switch. So I jumped it with the wire and the clutch does NOT engage. So should I leave the jumper wire in there and disconnect the connector to the compressor and see if the connector has power to it? If it does then it is likely the clutch? (the clutch turns freely by hand now). Thanks for the vid. Very informative! But still confused! FOLLOWING UP HERE: I just put a jumper wire on and I have power in the connector to the compressor. Does that mean my clutch is shot? How do I know that the whole compressor hasn't failed and not just the clutch? I just put a brand new AC Delco unit on a little over 2 years ago from Rockauto and now it's out of warranty! :(
Great video, thank you! In my case, sometimes times the clutch is engaging, sometimes not. When it doesn't, there is no ground at ac relay base load side, pin 87 (so bypassing pin 30 with 87 does not work). Pin 30 receives power each time. When it engages, compressor works fine, cold air is blown. What could cause the lack of ground on the load side of the relay base? from the climate control diagram, there is no other control between the clutch and AC relay, only a connector. Can it be only the wire/connector going to the clutch or also some other possible causes? many thanks!
I USED YOUR TIP TO PUT A BRIDGE BETWEEN 87 AND 30 TO KEEP THE COMPRESSOR ON WHILE I CHARGED THE AC SYSTEM WITH REFRIGERANT 134A,BECAUSE THE COMPRESSOR MUST BE ON TO FULLY CHARGE THE SYSTEM, THANKS FOR YOU TIP
Thanks again for the informative video. So I put the ignition key to on and used the jumper wire from pins 87 and 30 and the clutch clicked and I could see the clutch move in or out when using the jumper wire. Also the clutch couldn't be turned when it clicked or was engaged by use of the jumper. Doing this that way the ac clutch mini fuse didn't blow. The outcome to me suggests the possibility that the clutch wiring is ok or operating/ sending power to the clutch when the jumper is used. So I am going to replace the relay in hopes a relay fault is contributing to the 10 amp mini fuse blowing. I know the relay was quite warm when I first removed it.
@@m0bilemechanix After the old coil was removed and tested further it proved out that here was a short in the coil. When the new clutch assembly including the coil was replaced the clutch operated is it should and no more blown fuses! As well neither the relay nor the clutch diode were bad.
You should make a video with the power probe, i just bought myself one. My AC was working great but disengaged as i was setting in my car at work. Im hoping its only my high pressure switch or something in the line that caused the compressor to cut off all of a sudden. Thanks though.
i did the bypass clutch was engaging so i know clutch is good changed out the relay still nothing what else do you recomend i also could be low on freon also?when engaged i was getting hot air comming out no cold air does that mean i need freon
So I did this and the clutch turned on and cold ac started coming in but once I put the relay back it wouldn’t stay on, I also changed the horn relay and still turn on. A little advice would help
if not already discussed, most if not all vehicles have an ac limit switch which will kill the power to the clutch and not allow it to engage and turn the pump. Your clutch and pump could be totally fine so its important that you absolutely check this switch first , because if the refrigerant is low in the system, this switch will kill the power to the clutch as a safety measure to prevent damage to the rotating parts in the pump..
so you're saying even if the hotwire of 87/30 doesn't engage the clutch then it could just be the limit switch due to low refrigerant? When I put a screwdriver to the accumulator schrader valve I got pressure blowing out. So I think the pressure should be good enough.... is that not good enough sign?
That's correct the limit switch is triggered when the refrigerant level is low in the system because the refrigerant contains oil which lubricates the pump
@@jsugar72 by "AC Pump" you mean the other circuit in that same relay? You're saying that the AC Pump will engage the clutch even if the 87/30 circuit did not engage it? I hotwired 87/30 and nothing. So you're saying the AC Pump circuit will over ride the "limit switch" ? thanks
When you say 8730 I'm assuming you're talking about the AC relay. you can test your clutch to see if its operational without putting a pin or shorting the relay socket. unplug the power cord to your AC pump then get test leads and put 12 volt to the pins you pulled the power cord from and see if the clutch engages if it does your clutch is good. To test a relay I just pull the AC relay out and put another relay in from the distribution box there should be another 8730 in there or one similar
Not a pro: How is the pressure of the system? High and low side, the pressure has to be correct, to low or to high can cause the system to no function as well as a protective matter. The only way to test is with the AC gauges.
@@LifeBloodMarketing oh turns out I'm an idiot.. I had the valves closed on the car. 😅 So obviously refrigerant was not going. I also did not do a vaccum properly for the same reason 🤣. But I'm so dumb it didn't click to go ahead and pull a vaccum before opening the refrigerant can. So I was like well f it.. luckily it worked okay. Car gets cool enough. 🤷 Lessoned learned.
Pins 87 and 30 I would jump. Do I have to have the key on and the AC on hi to jp the relay? Because I understand the computer sends a ground to the black wire on the compressor. This is a 01 Pontiac Grand Prix SE.
No because the ground from ecm you are talking about is only activating the relay on the other pins. When you jump 87 and 30 you are bypassing all of that
@@m0bilemechanix Looking at the schematic for my car it showed one wire hot all the time and one wire hot with key on or running but I didn't have any power all the time with the car off at the relay with the key off I mean. I had power to one of the pins and when we jumped out 30 and 87 it did kick in. That house I have for the air conditioning can it's no good it's not allowing the fluid to come out the free on gas we have to try getting another hose
i have a directly related question. My AC fuse, relay and AC clutch are all good thanks to your video. But the AC high side pipe is not hot at all not even warm. But then I touched the high side pipe directly at the compressor output after a few seconds of running the AC and it was burning hot, could not keep my finger on it. Then i checked the high side coming out of the condenser and it was completely cold, not even warm. Does this mean there is a problem with the condenser ? Other things i checked : the fans are spinning. The low side pipe is just a little bit cool but barely at all, it's almost ambient temperature. Does the compressor output pipe being burning hot means the compressor is good ? Any other test i can do ?
You’re the man. I replaced my relay and didn’t know it needed to be in a certain way. Flipped it around and worked. Been going off and on by itself. Hopefully it’s stable now.
No the key can be out of the ignition for this specific test. The coil has a constant ground and when you jump 87 and 30 it takes power from the AC clutch fuse and applies it to the other side of the coil. The fuse has power at all times.
Thank you sir for the clear explanation. My AC is blowing warn air and the compressor is not engaging. I used your method and the compressor does engage once I jump the port 87 and 30 of the relay with a wire. But the compressor still doesn't engage after replacing the relay by a newly purchased one. I wonder, does this mean the circuit controls the relay is dead? What's the suggested next step to debug this issue? Looking forward to your suggestion.
.2000 Jeep Cherokee... i tried that relay bridge deal and the wire got hot and blew the big 20 amp ac fuse. does same thing when i try to bridge it over from the high side switch. . Compressor worked great in the other jeep. I start the car turn on A/C controls, Hi/max, When I unplug the ac compressor i still have power on the compressor end/plug but no power on the plug wire coming from the wiring harness. Only time that wire has power is when the ac is plugged in. Is that right?? My low pressure switch 4 ports has power on 3 out of 4 ports/slots. My high pressure switch 2 ports has power on both ports . it wont take freon.. ..{update } car running ac controls on, if i unplug my low side sensor i then have a hot and ground on the high side switch instead of 2 hots but still wont cycle the clutch but low side switch has 3 hot 1 neg. unplugged... i did test the wire thats going into that port and it has power going in the switch but no power in the port of the switch. If i hook the low side back up, again i got 2 hot ports on the high pressure switch. Even when i have 1 hot side other neg or no power on it. it still wont bridge over the clutch and when i got both sides hot and try bridge it it then will blow the big 20 amp fuse. So could my low pressure switch/connector be bad if so will that keep it from accepting freon.
If I can jumper the relay and the coil pulls in then I should look at the fuse? My coil pulls in when jumped at the relay and I have 35 psi on refrigerant gauge which indicates it's in correct range. What would next step be?
Nice video, thanks. I did this test this morning and my clutch and AC works fine. The relay is not faulty, there is no 12 volt to power it, I checked the 2 AC fuses, from there I don't know what to do, can it be the thermostat or software issues ? I have a Civic 2016. Thanks.
I'm just wondering why the ac compressor i just bought the clutch can barely turn it. And it comes with a paper saying it should be rotated at least 10 times using a spanner torque wrench. Never seen that before.
Jeez, I wish my alternator and compressor were easily accessible like that. I have an 03 Expedition and every thing is buried. I think my compressor coil is shorting out, keeps blowing the AC fuse when I turn it on and I'm dreading the replacement procedure. Ruled out the pressure switches, relay and diode. With the engine off, I removed the relay and jumped it and sure enough I was able to get the clutch to engage twice and then the fuse popped again. Next thing is to try again with the compressor electrical connector unplugged just to be sure. Its just a pain ind the ass to find the connector.
@@m0bilemechanix My car i20 engine is running very quiet as usual. However, as soon as AC clutch is engaged, I hear a squeak sounds and not metallic sounds or alike. The squeezing like sounds go away immediately as AC is off. Even with engine revs, same sounds. And with AC off, as I revs the engine, still the engine is quiet. How to find that squeaky like sounds and fix it? The AC is blowing cold. It seems the AC compressor is ok.
THANK YOU! you saved me at least $6-$700. I had a VERY low charge on the AC. Guages moved just a little when I hooked it up. I was able to get the clutch engaged with a jumper wire and I could get 2 cans into it. I can't thank you enough. I was already subbed to your channel, please keep offering work arounds and diagnosis for the average Joe. BTW I used 14 guage wire. I would suggest a smaller size like 18 guage. I had to keep one hand on the wire and another onthe freon/guage cluster. If the wire were smaller I probably could have stuck it into the relay port further where it would stay on its own.
my compressor is new i replaced it but still the clutch wouldnt kick on so i replaced the relay and it still didint work but when i try bypassing th e relay it works. is there a reason the relay is not working? also can i just leave it bypass for now or would that damage the ac compressor?
I have no power at my ac compressor, I was able to bump check it with wires and it clicks in and out . Is there a way to just run a new wire to a switch inside the car ?
You don't want to do that because there are safety switches that prevent low charge from ruining compressor and high pressure from exploding lines. The pressure can easily jump to over 500 psi under certain conditions and it can be dangerous if there aren't switches monitoring and regulating the compressor. If it's not coming on it means there is a problem. Best to just get it diagnosed so you don't ruin the compressor or have a line explode.
hey buddy you don't have an idea how long i been looking for this info!!! awesome video...one quick question ...can you tested with the ignition off/ on ??? thank you in advance and God bless you
How do you test the coil by the clutch? I’m sorry man I don’t have no one to really ask I just bought a 97 firebird and my ac doesn’t work but my heat does and I never been taught how to work on cars
That's the easiest access A/C compressor I've seen so far. Moment of silence for us front-wheel drive motor owners.
😂😂😂😂
Gotta love Jeeps
I'm working on a Chevy Silverado 2500 diesel. Looks exactly like this. Beautiful
Clear, simple and no bs. Excellent video! The a/c in my chevy Duramax appeared dead. Jumpered the relay as you directed and found life in the clutch. Added R-134a to the system and got cold air again! Apparently the a/c system is disabled when the refrigerant charge is low. Your video saved me time and money. Thanks!
Bingo. Thanks fer yer input!
Hey man thanks for posting this. 2014 Tacoma. AC light on, no clutch engagement. Removed relay, jumped the wires, clutch clicked. Went to Autozone, bought a can of stuff, jumped the wires with full fan and max ac, read 0 psi on the low side. Added enough R134 to get to about 40psi. Reinstalled relay, no engagement. Bought a new relay for $15 and whammo, everything working now. Was quoted $900 to replace my compressor after my "friend" listened to me talk about it and responded in like 2 seconds. Smh. $45 for the can o' stuff. I probably have a leak somewhere.
Thanks again!
Sounds like your friend deserves $200 for that brilliant advice he gave you
But typically we don’t think like that and rather pay complete strangers/other mechanics $900+
Thanks for this!!! Gone without a/c for a year in our 2011 Ford fusion and a shop wanted $1,800 to “revamp” the entire HVAC system because it would be “easier” to do. Thought my compressor went bad but using your testing method I found that mine is actually still engages. So which leads me to believe my Evap sensor has gone bad. So thank you! You’ve potentially saved me a lot of time and some money.
Great video. Most videos show you how it could go bad and what else to check but nobody was showing how simple it is to check if the ac compressor clutch is engaging.
Seems like every other video out there is all "replace the compressor", and mine ended up being a ground problem, saved a bunch of money , thanks
Mike White hi. What problems were you facing ??
how did you fix it what did you change/fix?
I think I may have the same problem, where was your ground problem?
What is the ground?
What is the ground?
For those who don't have the standard pin labels (30, 87...) and instead have (1,2,3,5), you want to place the wire in pins 3 and 5
Hell yes! Thanks man!! was looking everywhere for this comparison
I wired pins 1 and 5 and it worked
Hell yea bro this worked for me. Thanks! I bought a truck that was sitting for 5 years and wasn't sure if the compressor was bad or just needed recharged since the compressor wouldn't kick on while ac was turned on. Jumped the two leads and the clutch engaged
@@littledave232323 why 1 & 5?
@@mikeprice83071 and 5 work too because 1 is continuous 12v and 3 is the 12v that is received once the solenoid in the relay closes. Either way, you’re getting 12v so it works. 3 and 5 is the recommended method, 1 and 5 works just as fine.
Thank you for posting this video. I was able to get the compressor clutch to engage and charged my AC using your instructions on my Cadillac escalade. Now i have to figure out the right PSI for my system.
Thank you for the tips. Allowed me to successfully correct the hot air blowing from my AC. Apparently my compressor didnt have enough refrigerant to kick in - this bypass allowed it to filled. thanks again
Chris Cotten Yeah I was gonna ask the same thing before finishing the video! How do you fill your ac if the clutch won’t engage???
Derrick Smiley No as soon as I put the ac refill can on the low side and pulled the trigger ( while the car was running) it automatically turned on both ac fans! There’s a leak in my ac system so when it’s low it shuts down the ac compressor! Just have to get a black light to find the dye!
this is whats wrong with mine, blows hot air and clutch does not engage it has gas in so that was not low unless it is in the compressror
@@youtubebitchcenter1463 so if my clutch engages just like shown in video what is the problem
Great video. Just tested my compressor on my 06 Silverado and it works. Thanks for the info. Now time to find which sensor/switch is bad. Used my horn relay to test the a/c relay before and nothing happened. So I believe I do have a safety switch gone bad and possibly a leak in the system.
That was a great video! I applied this to my 04 Impala LS and the clutch did pull in. I also additionally disconnected the coolant Temp Sensor and started the car to make sure my AC Rad FANS were in working order as the AC fan was not working with the clutch not pulling in. Knowing that the relays and fans were good I went ahead and refilled the refrigerant and BLAMO! Everything is working great! Thanks man! Video helped alot!
This actually turned out helpful. Having a problem with my ac that keeps burning out the compressor fuse and i'm trying to figure out whether it's the clutch, wires or the relay.
Likely shorted wires or shorted coil
@@m0bilemechanix You helped me A TON. Greatly appreciate it
@@m0bilemechanix do I'm trying to figure out what I need to do..I'm no mechanic but I did exactly what you did in the video and my ac clutch did the same thing yours did it click on!!? So what do I need to do to fix it
Thankyou! FINALLY, an explanation that answers my questions and shows me the way to a fix on my Ranger! Most Excellent!
Thanks for the video. It worked perfectly on my 98' GMC truck. Was able to engage the clutch so I could recharge a completely empty system.
Yes pretty common and sometimes cheaply fixed
@@m0bilemechanix same with mine. Not enough R-134A to allow the clutch to engage. Worked awesome, and now my wife has a cool car, at least long enough to get to a garage to have the system looked at.
Why is this such a catch 22? Clutch wont engage with low refrigerant yet cant fill refrigerant unless clutch engages... is this how professional mechanics bypass this catch 22?
So what if this method does not work?
Well Eric you've done it again saved the day! Improvised tools beating the counter at the parts store once again! If you ever feel like letting me know how to go about replacing the wire that goes to the pressure switch please let me know as it has been discontinued. Thanks your pal Mopar Mike. Since they now own my behind. Lol
Should be able to just splice one in
@@m0bilemechanix you could recommend a place to buy the plug?
@@exiledintheus7251 might not be able to get one but I usually start with AutoZone and then I call the dealership. Tell them you need the pigtail for the pressure switch (witch ever you need high or low) of all else fails some salvage yards will let you cut one off a vehicle
@@m0bilemechanix I know this is old, but I replaced my high pressure switch on my 2007 Saturn Vue thinking it was the reason my AC went out. Before I put the new switch in, I could still hear the compressor turn on but after I replaced the switch the compressor wasn’t making anymore noise. I made sure I had enough refrigerant in the system and no leaks. I’m gonna give this a try later tonight when it “cools down” as it’s already in the triple digits here and I’m dying with no AC. Thanks to TH-cam videos, I never knew a girl like me would be able to learn/do so much work on my own car!
Thanks for the tutorial!! In my case, after doing all this I found the large connector behind the clutch to be a bad contact...Check your connections too folks!
Yes very easy to forget about connectors
Thanks I will be investigating the wiring to compressor more closely.
i know im asking randomly but does someone know of a trick to log back into an instagram account?
I was dumb forgot my login password. I would love any tricks you can give me
@Cairo Gus instablaster =)
@Case Leonard thanks so much for your reply. I got to the site on google and im trying it out now.
Seems to take quite some time so I will get back to you later with my results.
Thank you so much you were more helpful than most of these damn videos on TH-cam
Thanks bud! I did this on my Grand Prix like 5 years ago so I forgot how to do it. My brother in law has a Lincoln which he filled with Free-on but the clutch did not engage so I wanted to test it this way to see if that works at all.
I was thinking of a way like that but didn't know exactly how. Will try this on my truck and hope my ac compressor is still good
I tried your method and my AC compressor was good, I recharged the system with UV die to find out if it has a leak. The AC blows cold now and I can't see any leaks yet.
@@jdenha7078 so you just had low Freon probably the low pressure switch kept the Ac from running. I’m having the same issue I checked relay even swapped relays around and still nothing fuse not blown and AC diode checked good. The AC button lights up so I’m sure that’s working but the relays not be commanded on so no powers hitting the Ac clutch. Maybe I’m low on Freon
@@ryans413 I actually found the leak using the UV dye. It was coming from the o rings. So now I am out of AC again I guess it's time to change the O-rings and then recharge the system.
Our van, the cluch engagesn and immediately disengages. I'm guessing the relay is bad or the low pressure is just enough to get it to engage then disengage. Hopefully the compressor is still good :)
@@auggiebendoggy try removing 1 of the shims its likely the "gap" is too large
Straight and to the point. Lots of hair on the knuckles; good sign of a seasoned mechanic.
pre clean finger nailed latex glove mechanics . always thought that was amusing
Why my compressor clutch not engaging when i do this same test on my car relay box,and when I test direct to my battery the compressor clutch is working.whats the problem on this situation?hope you notice me sir thankyou!
I'm looking for this answer!
After relay u have trinary switch who controls ac compressor if pressure is low or u have leak somewhere because trinary switch compressor will not start.
Safe measure
Or faulty switch can be problem to
That's an awesome engine bay design .. seems like the alternator is also on top. No need to get under the car or remove the tire. My quest sucks with space. Lol
Question if I connected a jumper wire to the 87 and to the 30 but the compressor did not make any clicking noise is it a bad connection or a bad clutch or a bad compressor?
Very good vidéo, well explained. It worked perfect for me, just cut myself a bit of wire and tried it. Didn't clic that loud for me, but with a video I could see it engaged well. Replaced the relay and solved! Thanks!
Thanks for the tips, very helpful places to start looking. Btw if ur amp power cable is still loose like that, you’ve gotta loom and secure it around the main engine area, ideally similar to OEM wiring paths, and grommet thru the firewall if u can’t find a punch out. Same goes for all cabling. Clean secure adequately sized grounds to chassis/frame are key! Extra bonus points for extra clean wiring cuz u know it’s solid and very easy to work on if needed later. And u certainly should do a big 3 / 4 upgrade or at least the battery ground wire for best results regardless of draw cuz oem wires are cheap and puny.
This is what I was looking for - explained everything! LR Discovery 2 with original factory air - blowing warm air now after 16 years - was hoping it was just the ac compressor clutch/solenoid (it recently stopped engaging). It's a Denso compressor; will do your check as described here and hopefully it is the clutch/solenoid at fault and I can replace myself without having to have the system degassed and spend bug $$$ on a new compressor! The system is fully charged with R134A gas now. Probably also worth replacing the receiver/drier, but I guess that would mean degassing the system as well.
Thank you!
Starts at 2 min mark, better at 2x speed.
Thank You this was the exact video I was looking for.
Thanks man! I was able to confirm my clutch and compressor worked using your method.
Nice!
Thanks. I just got a quote for $2500 to replace my a/c so i wanna go through and see if i can fix it on my own and this video is a great place to start
Did you find the problem
God I hope he didn't pay $2,500 to have his ac fixed. Thats highway robbery.
Holy shit my guy
Just what I needed to lock up my AC clutch- thanks!
got a 2001 GMC Sierra 1500.....my clutch is not engaging at all....got no power with voltage tester to any pressure switches or recirc switch. So I jumped it with the wire and the clutch does NOT engage. So should I leave the jumper wire in there and disconnect the connector to the compressor and see if the connector has power to it? If it does then it is likely the clutch? (the clutch turns freely by hand now). Thanks for the vid. Very informative! But still confused! FOLLOWING UP HERE: I just put a jumper wire on and I have power in the connector to the compressor. Does that mean my clutch is shot? How do I know that the whole compressor hasn't failed and not just the clutch? I just put a brand new AC Delco unit on a little over 2 years ago from Rockauto and now it's out of warranty! :(
Short sweet and to the point whithout bs,, thanks
Nice video on the testing.You can get a compressor for 150.00.
Great video, thank you!
In my case, sometimes times the clutch is engaging, sometimes not. When it doesn't, there is no ground at ac relay base load side, pin 87 (so bypassing pin 30 with 87 does not work). Pin 30 receives power each time. When it engages, compressor works fine, cold air is blown. What could cause the lack of ground on the load side of the relay base? from the climate control diagram, there is no other control between the clutch and AC relay, only a connector. Can it be only the wire/connector going to the clutch or also some other possible causes?
many thanks!
I USED YOUR TIP TO PUT A BRIDGE BETWEEN 87 AND 30 TO KEEP THE COMPRESSOR ON WHILE I CHARGED THE AC SYSTEM WITH REFRIGERANT 134A,BECAUSE THE COMPRESSOR MUST BE ON TO FULLY CHARGE THE SYSTEM, THANKS FOR YOU TIP
Did it work and engage after that I think mines low too cause the clutch won’t engage at all
Bloody legend... cheers mate from Oz. 👍👍👍
Thanks for saving me money found a broken ground wire on my kw t680
Very helpful video. Straight to the point and informative. Thank you.
Thanks again for the informative video. So I put the ignition key to on and used the jumper wire from pins 87 and 30 and the clutch clicked and I could see the clutch move in or out when using the jumper wire. Also the clutch couldn't be turned when it clicked or was engaged by use of the jumper. Doing this that way the ac clutch mini fuse didn't blow. The outcome to me suggests the possibility that the clutch wiring is ok or operating/ sending power to the clutch when the jumper is used. So I am going to replace the relay in hopes a relay fault is contributing to the 10 amp mini fuse blowing. I know the relay was quite warm when I first removed it.
Seems unlikely. I would suspect an intermittent short in the wiring to the compressor clutch or a bad coil due to high resistance/intermittent short.
@@m0bilemechanix After the old coil was removed and tested further it proved out that here was a short in the coil. When the new clutch assembly including the coil was replaced the clutch operated is it should and no more blown fuses! As well neither the relay nor the clutch diode were bad.
Great video man, I appreciate you taking the time to get this info out there
You should make a video with the power probe, i just bought myself one. My AC was working great but disengaged as i was setting in my car at work. Im hoping its only my high pressure switch or something in the line that caused the compressor to cut off all of a sudden. Thanks though.
Best video made by a werewolf
Now that's funny!
Lol I didn't get it until I saw that arm. 😂
I’m glad somebody said it LOL LOL LOL I was waiting for claws
Very good explanation on how this works, thanks!
Thank you for the video , that's what I needed to see. Thanks again
Thank you for the kind comment
@@m0bilemechanix ¹
So what do I when my fuse won’t engage the ac clutch ? I brought New fuses and they don’t work but it works if I jump it.
seems like from others responses, try looking at the ground for the relay.
Very clear and concise video. Thank you.
Does the key need to be turned on to check..
Nope
Damn, new compressor then. Thanks for responding.
@@thalverlisgriffin keep in mind this test can only prove that your coil is working. It can't tell you what is wrong
i did the bypass clutch was engaging so i know clutch is good changed out the relay still nothing what else do you recomend i also could be low on freon also?when engaged i was getting hot air comming out no cold air does that mean i need freon
This is a great video my clutch is permanently engaged so will not run free ?
So I did this and the clutch turned on and cold ac started coming in but once I put the relay back it wouldn’t stay on, I also changed the horn relay and still turn on. A little advice would help
If clutch engages with the wire trick that means I need a new relay fuse correct ?
Yes, and some also have a fuse for the clutch.
There is also a 10 amp mini fuse behind the relay. That was blown in mine. 02 Sierra.
if not already discussed, most if not all vehicles have an ac limit switch which will kill the power to the clutch and not allow it to engage and turn the pump. Your clutch and pump could be totally fine so its important that you absolutely check this switch first , because if the refrigerant is low in the system, this switch will kill the power to the clutch as a safety measure to prevent damage to the rotating parts in the pump..
so you're saying even if the hotwire of 87/30 doesn't engage the clutch then it could just be the limit switch due to low refrigerant? When I put a screwdriver to the accumulator schrader valve I got pressure blowing out. So I think the pressure should be good enough.... is that not good enough sign?
That's correct the limit switch is triggered when the refrigerant level is low in the system because the refrigerant contains oil which lubricates the pump
Put 12 volts to your AC pump and see if the clutch engages
@@jsugar72 by "AC Pump" you mean the other circuit in that same relay? You're saying that the AC Pump will engage the clutch even if the 87/30 circuit did not engage it? I hotwired 87/30 and nothing. So you're saying the AC Pump circuit will over ride the "limit switch" ? thanks
When you say 8730 I'm assuming you're talking about the AC relay. you can test your clutch to see if its operational without putting a pin or shorting the relay socket. unplug the power cord to your AC pump then get test leads and put 12 volt to the pins you pulled the power cord from and see if the clutch engages if it does your clutch is good. To test a relay I just pull the AC relay out and put another relay in from the distribution box there should be another 8730 in there or one similar
Thank you so much for the video, I now don't need a new compressor!
You definitely got me on the right track on troubleshooting this on my super duty! Thanks Bro!
Thank you! I have seen other videos with this info. Yours is the best!!☺☺👍👍
Great Info - thanks for taking the time to pass this info on....I appreciate it
Appreciate the video. Oldie but goodie.
Very nice rugged hands and forearms!
Not sure about this one but I'll take it! Thanks lol.
Very Useful Video....thank you for taking the time to make it and explain it well..
Mines clicks.. however when I add refrigerant it won't kick on?
Btw.. you are super lucky your ac is in such an easy to reach place.
Not a pro: How is the pressure of the system? High and low side, the pressure has to be correct, to low or to high can cause the system to no function as well as a protective matter. The only way to test is with the AC gauges.
@@LifeBloodMarketing oh turns out I'm an idiot.. I had the valves closed on the car. 😅 So obviously refrigerant was not going. I also did not do a vaccum properly for the same reason 🤣. But I'm so dumb it didn't click to go ahead and pull a vaccum before opening the refrigerant can. So I was like well f it.. luckily it worked okay. Car gets cool enough. 🤷 Lessoned learned.
Pins 87 and 30 I would jump.
Do I have to have the key on and the AC on hi to jp the relay?
Because I understand the computer sends a ground to the black wire on the compressor. This is a 01 Pontiac Grand Prix SE.
No because the ground from ecm you are talking about is only activating the relay on the other pins. When you jump 87 and 30 you are bypassing all of that
@@m0bilemechanix
I understand thank you
@@m0bilemechanix
Looking at the schematic for my car it showed one wire hot all the time and one wire hot with key on or running but I didn't have any power all the time with the car off at the relay with the key off I mean. I had power to one of the pins and when we jumped out 30 and 87 it did kick in. That house I have for the air conditioning can it's no good it's not allowing the fluid to come out the free on gas we have to try getting another hose
We had to get some kind of adapter from Napa something about an old style hose with a new style cans it worked though.
Thanks for the video best one yet,thanks
Great video and an awesome explanation!
i have a directly related question. My AC fuse, relay and AC clutch are all good thanks to your video. But the AC high side pipe is not hot at all not even warm. But then I touched the high side pipe directly at the compressor output after a few seconds of running the AC and it was burning hot, could not keep my finger on it. Then i checked the high side coming out of the condenser and it was completely cold, not even warm. Does this mean there is a problem with the condenser ?
Other things i checked : the fans are spinning. The low side pipe is just a little bit cool but barely at all, it's almost ambient temperature. Does the compressor output pipe being burning hot means the compressor is good ? Any other test i can do ?
You’re the man. I replaced my relay and didn’t know it needed to be in a certain way. Flipped it around and worked.
Been going off and on by itself. Hopefully it’s stable now.
Are you doing this with the ignition key turn to accessory? In other words to run this test!
Yes the relay gets its power from the ignition and is commanded on by the PCM
No the key can be out of the ignition for this specific test. The coil has a constant ground and when you jump 87 and 30 it takes power from the AC clutch fuse and applies it to the other side of the coil. The fuse has power at all times.
Excellent service and it was great appreciate it good job
Worked for 97 Silverado. It was the 85 and 30 (still diagonal). Thanks.
Thank you sir for the clear explanation. My AC is blowing warn air and the compressor is not engaging. I used your method and the compressor does engage once I jump the port 87 and 30 of the relay with a wire. But the compressor still doesn't engage after replacing the relay by a newly purchased one. I wonder, does this mean the circuit controls the relay is dead? What's the suggested next step to debug this issue? Looking forward to your suggestion.
I’m having the same issue now once I jump it it works fine but when a new relay is in it doesn’t work
.2000 Jeep Cherokee... i tried that relay bridge deal and the wire got hot and blew the big 20 amp ac fuse. does same thing when i try to bridge it over from the high side switch. . Compressor worked great in the other jeep. I start the car turn on A/C controls, Hi/max, When I unplug the ac compressor i still have power on the compressor end/plug but no power on the plug wire coming from the wiring harness. Only time that wire has power is when the ac is plugged in. Is that right?? My low pressure switch 4 ports has power on 3 out of 4 ports/slots. My high pressure switch 2 ports has power on both ports . it wont take freon.. ..{update } car running ac controls on, if i unplug my low side sensor i then have a hot and ground on the high side switch instead of 2 hots but still wont cycle the clutch but low side switch has 3 hot 1 neg. unplugged... i did test the wire thats going into that port and it has power going in the switch but no power in the port of the switch. If i hook the low side back up, again i got 2 hot ports on the high pressure switch. Even when i have 1 hot side other neg or no power on it. it still wont bridge over the clutch and when i got both sides hot and try bridge it it then will blow the big 20 amp fuse. So could my low pressure switch/connector be bad if so will that keep it from accepting freon.
If I can jumper the relay and the coil pulls in then I should look at the fuse? My coil pulls in when jumped at the relay and I have 35 psi on refrigerant gauge which indicates it's in correct range.
What would next step be?
Nice video, thanks. I did this test this morning and my clutch and AC works fine. The relay is not faulty, there is no 12 volt to power it, I checked the 2 AC fuses, from there I don't know what to do, can it be the thermostat or software issues ? I have a Civic 2016. Thanks.
Thanks bud you just got my cold air going again
Glad it helped!
Master thank you very much and greetings from Algeria
I'm just wondering why the ac compressor i just bought the clutch can barely turn it. And it comes with a paper saying it should be rotated at least 10 times using a spanner torque wrench. Never seen that before.
Jeez, I wish my alternator and compressor were easily accessible like that. I have an 03 Expedition and every thing is buried. I think my compressor coil is shorting out, keeps blowing the AC fuse when I turn it on and I'm dreading the replacement procedure. Ruled out the pressure switches, relay and diode. With the engine off, I removed the relay and jumped it and sure enough I was able to get the clutch to engage twice and then the fuse popped again. Next thing is to try again with the compressor electrical connector unplugged just to be sure. Its just a pain ind the ass to find the connector.
Yea man all cars are pain in the asses lol
Good vid man. Thanks for taking the time to do it.
thanks for watching and commenting
@@m0bilemechanix My car i20 engine is running very quiet as usual. However, as soon as AC clutch is engaged, I hear a squeak sounds and not metallic sounds or alike. The squeezing like sounds go away immediately as AC is off. Even with engine revs, same sounds. And with AC off, as I revs the engine, still the engine is quiet. How to find that squeaky like sounds and fix it?
The AC is blowing cold. It seems the AC compressor is ok.
Thanks for making this video very HELPFUL 👍🏼👍🏼
Thank you for the very nice video. Can you please explain if the clutch doesn't engage and you have no voltage there; what is the next step?
Did you find the answer to this
THANK YOU! you saved me at least $6-$700. I had a VERY low charge on the AC. Guages moved just a little when I hooked it up. I was able to get the clutch engaged with a jumper wire and I could get 2 cans into it. I can't thank you enough. I was already subbed to your channel, please keep offering work arounds and diagnosis for the average Joe. BTW I used 14 guage wire. I would suggest a smaller size like 18 guage. I had to keep one hand on the wire and another onthe freon/guage cluster. If the wire were smaller I probably could have stuck it into the relay port further where it would stay on its own.
Your math adds up to a $694 variation in potential spending.
@@gavinvalentino1313o if my clutch is engaging just like his did what would the problem be ???
Video is good to go. Thank you for posting.
Do you have to turn the key so the battery can be turned on? And then you do the steps that you showed?
Do I need to have the ignition on to check this?
No
Do you put the relay back in place after jumping?
What wire should I buy to test? I'm in AutoZone and see wire with different gauges.
my compressor is new i replaced it but still the clutch wouldnt kick on so i replaced the relay and it still didint work but when i try bypassing th e relay it works. is there a reason the relay is not working? also can i just leave it bypass for now or would that damage the ac compressor?
I have no power at my ac compressor, I was able to bump check it with wires and it clicks in and out . Is there a way to just run a new wire to a switch inside the car ?
You don't want to do that because there are safety switches that prevent low charge from ruining compressor and high pressure from exploding lines. The pressure can easily jump to over 500 psi under certain conditions and it can be dangerous if there aren't switches monitoring and regulating the compressor. If it's not coming on it means there is a problem. Best to just get it diagnosed so you don't ruin the compressor or have a line explode.
What car are you doing the demonstration on? Thanks
99 gmc Sierra
I need help. I replaced the pressure switch and also removed relay for clutch and it will not disengage. Is the clutch going bad?
Do u have to disconnect the wires from the battery before u do this?
No. The battery needs to be hooked up.
hey buddy you don't have an idea how long i been looking for this info!!! awesome video...one quick question ...can you tested with the ignition off/ on ??? thank you in advance and God bless you
I have the same question. Did you ever find the answer anywhere else? Thanks
Hi Sir, Thank you for posting this useful video. You need to turn the car on without starting the engine to test it, right?
How do you test the coil by the clutch? I’m sorry man I don’t have no one to really ask I just bought a 97 firebird and my ac doesn’t work but my heat does and I never been taught how to work on cars
What if clutch does engage when bypassed and refrigerant is good but still not cooling?
So if you have to bypass it is it the switch the relay that's bad?
Awesome information thanks man. Looks like all I need is a new fuse after doing your test. 👍👍
So, if it click what you do?
I just replace compressor but still clutch doesn't engage. Doing this wil determine what?
How many dc volts have to engage the compressor?
Anything over 10 or 11 should do it.
Do you know what voltage runs to the compressor for it to engage? Is it 12v?
Battery power. This can range anywhere from 12v to 14.5v
@@m0bilemechanix Thanks!