A/C compressor clutch not turning on?

Tiny
COTYRLONG
  • MEMBER
  • 2003 MINI COOPER S
  • 4 CYL
  • 2WD
  • MANUAL
  • 90,000 MILES
My A/C stopped working so I replaced the A/C compressor clutch which worked for a few weeks then it started whining and eventually the A/C totally stopped working. So, I bought a compressor and before installation had the Freon extracted then put back in professionally when finished. Again after a few weeks the A/C doesn’t work 90% of the time. On my way to work in the morning the A/C works great cold as ice but then from lunch time on the clutch and fans don’t even kick on. Since replacing it we had the machine hooked up and both low and high side are correct pressure and has no leaks. I’m stumped on what it can be with it only working when slightly colder out but not when it’s hot out and it being cold as ice when it does work.
Thursday, July 20th, 2023 AT 3:48 PM

21 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,244 POSTS
Hi,

Have you checked or replaced the compressor clutch relay? It may be getting affected by the heat.

I attached a pic below that shows what I'm referring to. Switch that relay with a different one having the same part number and see if it will work. If there isn't one, here is a link that explains how to test a relay:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Let me know what you find. One other thought. When it doesn't engage, check to see if there is power to the red wire at the compressor clutch.

Take care,

Joe

See pic below.
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Thursday, July 20th, 2023 AT 8:54 PM
Tiny
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I tried “jumping” the relay to c if it would force on, but it didn’t do anything. And I switched the relay with the fan relay and the fan kicked on rite away but still no clutch engages. I could buy a new relay tomorrow just to c. And at work tomorrow I’ll check the wire on the clutch compressor to c if it has power. Thanks for the help I Appreciate it I’ll message tomorrow with an update.
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Thursday, July 20th, 2023 AT 9:25 PM
Tiny
JACOBANDNICKOLAS
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Hi,

If the condenser fan is turning on, there is a good chance the compressor clutch is getting power. However, please confirm that and let me know. If it is getting power and not engaging, the clutch coil is likely bad.

Let me know.

Joe
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Friday, July 21st, 2023 AT 7:18 PM
Tiny
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First thing I noticed was the ambient air temperature sensor isn’t in the bumper like it should be. It was behind the radiator, could that be the cause? I’m checking a couple other things now then I’m going to get the bumper off and put it where it belongs.
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Saturday, July 22nd, 2023 AT 10:16 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

I don't feel the sensor would prevent the compressor from engaging. Were you able to check the compressor clutch for power?

Let me know.

Joe
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Saturday, July 22nd, 2023 AT 9:33 PM
Tiny
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Okay, so, apparently my low-speed fan does not work, it’s only the high speed that works. But when I put power to each of the terminals for some reason the high speed starts out real slow then doesn’t even almost go to full speed but when the car is on it works fine. And on the low speed it doesn’t do anything at all and from what I’m seeing if the low-speed fan doesn’t work the clutch won't engage so I ordered a resistor to bypass the original resistor it’ll be here tomorrow. I just got the bumper off to check to c if there’s power to the compressor and if I can get the clutch to engage. I have 2 small kids so it’s almost impossible to do a job like this when I want. I’ll get back to Ya with what I figure out.
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Sunday, July 23rd, 2023 AT 4:07 PM
Tiny
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And I gladly will be donating to this site it’s near impossible to find help like this. I’ll definitely be recommending it to family and friends.
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Sunday, July 23rd, 2023 AT 4:08 PM
Tiny
JACOBANDNICKOLAS
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Hi,

Thank you for the update, and I'm happy to help. Life has become much more expensive over the past couple of years, so if I can help, I want to.

The most important thing to remember is first, take good care of the kids. They are the future, and we need good people. LOL

Let me know how things turn out for you.

Joe
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Sunday, July 23rd, 2023 AT 6:40 PM
Tiny
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I can’t access the wire on the compressor without removing a bunch of stuff or the compressor its self but other than that I got a new resistor to bypass the origins hoping the low-speed fan would kick on but that didn’t work. And also hooking 12v to the compressor relay didn’t turn it on. And on Saturday my high speed fan came on and stayed on until it drained my battery so I just left it and today as soon as I put jumper cables on it the high speed fan turned on so I started the car let it run then again when turning it off the fan stayed on so I just pulled the fuse. I guess I’m going to take it to a shop I’m tired of dealing with this. I paid for a warranty through my financing company so hopefully they’ll pay to have it fixed. Thanks for all your help but I’m over this project usually I’m pretty good at figuring stuff out but I’m feeling pretty defeated.
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Monday, July 24th, 2023 AT 8:00 PM
Tiny
JACOBANDNICKOLAS
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Hi,

I totally understand. However, if you ran power from the compressor relay to the compressor, it should have engaged. I can't be sure, but I believe the clutch coil is faulty.

If possible, could you let me know what is found? I'm interested in knowing.

Take care,

Joe
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Monday, July 24th, 2023 AT 9:49 PM
Tiny
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My big thing was there’s no way I bought a clutch that only lasted a couple months then bought a compressor and that to only lasted a month. But to be honest that’s 100% my luck I’d buy 2 faulty parts. But you I’ll let you know as soon as it’s fixed.
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Tuesday, July 25th, 2023 AT 6:19 AM
Tiny
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One more question. Can a bad intercooler cause any of the issues I’m having? I was just going through my head when the A/C stuff started, and it was right around the same time I got a bigger intercooler for the car. But idk if they would have anything to do with each other.
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Tuesday, July 25th, 2023 AT 3:54 PM
Tiny
JACOBANDNICKOLAS
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Hi,

I don't see any connection between the intercooler and the compressor. The only thing I can think of is if the wiring was damaged or disconnected without you knowing when you installed the new part.

I look forward to hearing what you find out from the shop. This is certainly an interesting one. Also, if it makes you feel any better, I have the exact same luck. LOL

Take care,

Joe
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Tuesday, July 25th, 2023 AT 8:41 PM
Tiny
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I told the shop not to continue with any work. He’s trying to charge me $140 an hour and charge me $150 for a diagnosis. And all the diagnosis was him saying I need to get a new wire harness for the car because I have aftermarket fog lights. So it’s possible that they fried the wire harness so once I get a new one then he can diagnose again. Which is absolute bull**** because the fog lights came with its own harness with an inline fuse and resistor and all that all ya had to do was connect it to a power source so it’s not ghetto wired, and they’ve been installed for 6 months now with no issues. So, the mystery still remains. I’m going to take the compressor off and use the warranty on it for a new one and just replace it myself and hopefully it’ll just be a faulty compressor.
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Saturday, August 5th, 2023 AT 10:08 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

Did you check to see if there is power to the compressor? If you jump it at the relay, will it engage? These are just easier ways to check before you go to the trouble of removing the compressor,

Let me know.

Joe
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Saturday, August 5th, 2023 AT 3:42 PM
Tiny
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I picked up the car and the A/C worked for about 20 minutes ice cold then I heard it disengage and that was it, it didn’t work anymore, but the high-speed fan seems to be working properly now it was kicking on and off. When I got home after an hour's drive it turned off with the car instead of staying on and draining the battery. But previously yes, I put 12v to where the relay goes, and it did nothing. Wait would the car have to be on even if I’m using a totally separate power source? And there’s 2 wire connectors for the fans, there’s one bigger one with like idk 4 wires in it and there’s another one with just 2 wires. Is there a way to test them to see if they work with a separate power source or something? Idk I’m decent with cars but wiring I'm only half decent and air conditioning I know nothing. Thanks again for the help I don’t know anywhere else where someone would be this helpful and dedicated.
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Saturday, August 5th, 2023 AT 11:58 PM
Tiny
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One more update. Just got done driving the car for about an hour round trip and the A/C worked for the first 25-30 minutes, then stopped. Fans sounded like they were working as they should and turned off when I turned off the car.
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Sunday, August 6th, 2023 AT 7:33 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

First, you are very welcome. I just hope we can figure this out. As far as your question, if you are providing power directly to the relay and the clutch doesn't engage, either we have a broken wire or a faulty clutch coil. Also, you don't need to have the key on if the power is direct. You are controlling it.

Were you able to check if there is power to the compressor clutch?

Let me know.

Joe
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Sunday, August 6th, 2023 AT 9:44 PM
Tiny
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How exactly do I check for power to the clutch?
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Monday, August 7th, 2023 AT 6:24 AM
Tiny
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The compressor I have has a warranty and they ordered it yesterday so today I’m going to get the old one off and put the new one on and see if that fixes it and if not then I can start digging into other stuff. I figured while it’s out I can check the wiring to make sure it’s all good and see if the clutch spins freely or not.
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Monday, August 7th, 2023 AT 6:26 AM

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