A/C clutch not working

Tiny
TONY02
  • MEMBER
  • 2004 CHRYSLER PT CRUISER
  • 160,000 MILES
So recently I did a timing belt job on my car listed above and I discharged the A/C system and when I was ready to put refrigerant back in it the A/C clutch wasn’t kicking on. So I ended up jumping the relay and it turned on and now the system is fully charged. But my A/C clutch still isn’t turning on by itself. I swapped the relay and still nothing. I checked the fuses and it’s all good. I also replaced the low pressure switch on it and I’m still getting nothing. Any advice on what I should do next? It seems that the only way the A/C clutch turns on is when I jump the relay.
Friday, May 8th, 2020 AT 10:18 AM

26 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good afternoon,

I attached a wiring diagram for the A/C compressor.

Can you remove the relay and with the key on? you should have 2 powers in the connector.

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

Can you verify this?

Can you check for power as well at the high and low pressure switches?

https://www.2carpros.com/articles/how-to-check-wiring

Roy
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Friday, May 8th, 2020 AT 10:36 AM
Tiny
TONY02
  • MEMBER
  • 74 POSTS
Okay, so with the key on at the relay I do have two power connectors, but as for the high and low pressure switches I have nothing, but when I turn the car on and A/C on I do get a ground at both switches but no power.
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Friday, May 8th, 2020 AT 6:00 PM
Tiny
ASEMASTER6371
  • MECHANIC
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The power for the switches comes from the control head. If there is no power, go to the control head and see if the wire, brown, has power when the A/C is commanded on.

If it does, you have a wiring issue, if it does not, then the control head is bad.

Without the signals from the 2 pressure switches, the PCM will not ground the control side of the A/C relay for the compressor to come on.

Roy
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Saturday, May 9th, 2020 AT 1:54 AM
Tiny
TONY02
  • MEMBER
  • 74 POSTS
The control head would be inside the car right the instrument panel that controls all the A/C stuff by the radio? If so then yea the brown wire isn’t getting no power so that would mean the control head is bad then?
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Saturday, May 9th, 2020 AT 8:54 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
That is correct. That is where the power comes from.

I attached a picture of the control for you.

Roy
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Sunday, May 10th, 2020 AT 2:26 AM
Tiny
TONY02
  • MEMBER
  • 74 POSTS
Okay, thanks so much for the help. I will go head and replace it and I’ll update it when I do.
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Sunday, May 10th, 2020 AT 5:34 AM
Tiny
ASEMASTER6371
  • MECHANIC
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You are welcome.

Always glad to help.

Roy
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Sunday, May 10th, 2020 AT 5:35 AM
Tiny
TONY02
  • MEMBER
  • 74 POSTS
Hey, so I know it’s been a while but I finally had a chance to replace the control head with a brand new one but still the A/C clutch doesn’t engage. I also back probed it to check for power at the brown wire and I still have nothing.
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Tuesday, May 19th, 2020 AT 6:36 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Okay, when you checked the brown wire, was the engine running and the A/C commanded on?

Roy
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Wednesday, May 20th, 2020 AT 6:17 AM
Tiny
TONY02
  • MEMBER
  • 74 POSTS
Yes, I put the A/C on high.
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Wednesday, May 20th, 2020 AT 10:56 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
If you disconnect the connector with the key on, does the brown wire have any power?

Roy
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Wednesday, May 20th, 2020 AT 11:03 AM
Tiny
TONY02
  • MEMBER
  • 74 POSTS
No the brown wire doesn’t have any power.
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Wednesday, May 20th, 2020 AT 11:26 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
I attached a wiring diagram for you.

check the voltage on both sides of the fuse with the key in the on position.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Roy
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Wednesday, May 20th, 2020 AT 11:33 AM
Tiny
TONY02
  • MEMBER
  • 74 POSTS
Okay, so I checked the fuses you said to check and they are good. I used a test light connected to battery ground and it lit up on both sides for all of them.
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Wednesday, May 20th, 2020 AT 5:36 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Okay, it is pointing right back to the control head again.

Where did you get the control head?

Roy
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Thursday, May 21st, 2020 AT 4:21 AM
Tiny
TONY02
  • MEMBER
  • 74 POSTS
I got it at AutoZone.
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Thursday, May 21st, 2020 AT 6:02 AM
Tiny
ASEMASTER6371
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I would return it for another one.

All tests show it is this unit that is bad.

Roy
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Thursday, May 21st, 2020 AT 6:07 AM
Tiny
TONY02
  • MEMBER
  • 74 POSTS
Okay, I returned it and got another one at O'Riley’s. I will update when it comes in to see if it’s good or not.
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Thursday, May 21st, 2020 AT 10:29 PM
Tiny
ASEMASTER6371
  • MECHANIC
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Sounds like a plan.

We will be here.

Roy
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Friday, May 22nd, 2020 AT 4:08 AM
Tiny
TONY02
  • MEMBER
  • 74 POSTS
Okay, so it came and and I installed it and still same thing I’m not getting power at the brown wire and the clutch isn’t engaging. At this point I’m thinking of just jumping the relay with a jumper wire and leaving it like that, but my only concern is will this mess up the compressor by having the clutch engaged at all times?
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Thursday, May 28th, 2020 AT 4:08 PM

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