05 Yukon AC Clutch is Stuck

Disclaimer: I am very new to all of this. I didn’t know how to change my oil and had never changed a tire like 2 months ago. I’ve been lurking here and trying to learn on my own and fix any issues with my Yukon.

I’ve been having AC issues and everything tests good but the clutch was not engaging and compressor would not turn on. When I turn the AC on, the snowflake comes up and is not blinking.

A shop near me told me it was the HVAC control module. I replaced it with a Dorman unit, just to see, and nothing changed. They properly emptied the refrigerant and refilled, added some dye, and said they didn’t see any leaks. I tested the high pressure switch (I think it’s the high pressure, it’s the one attached to the accumulator) and tested the wiring, both tested okay. 5v at the wiring harness and I can’t remember what the switch was reading but I believe it was between 0.4-4.25 volts.

Yesterday I tapped the clutch in a bit with the engine running and the compressor kicked on for the first time in a very long time. However, now it is stuck. If the engine is running, the compressor is running. I haven’t driven it or left it running for long because I’ve read that the compressor is supposed to cycle, and since it would not be cycling, I didn’t want to damage anything more than it already is.

Would it be best to just have the system evacuated and replace the whole compressor, or would it be cheaper/possible to only replace the clutch?

Any advice is much appreciated.

I would disconnect the wire going to the clutch and see if the clutch lets go. That would tell you for sure if it is stuck or you have electrical problems.

Just remove the A/C belt so you can drive it, and until you can get it diagnosed.

DRLexpress said:

I would disconnect the wire going to the clutch and see if the clutch lets go. That would tell you for sure if it is stuck or you have electrical problems.

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This here. If it stays while unpowered the clutch is damaged. You can replace it without removing the compressor. I've don't that on my Silverado.
If it disengages, move to the fuse box and pull the relay. See if it disengages. If so swap the relay with maybe the horn relay, and see if it stays engaged. If not the relay is stuck and needs replaced. If it stays engaged, then move to the hvac controller.
Easiest way to find an electrical issue( for a beginner) is start furthest from the power source and work backwards.

DRLexpress said:

I would disconnect the wire going to the clutch and see if the clutch lets go. That would tell you for sure if it is stuck or you have electrical problems.

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Okay good call, I’ll try that out today and see what happens.

Fless said:

Just remove the A/C belt so you can drive it, and until you can get it diagnosed.

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Why did I not think of this? Will do, thank you!

Mudsport96 said:

This here. If it stays while unpowered the clutch is damaged. You can replace it without removing the compressor. I've don't that on my Silverado.
If it disengages, move to the fuse box and pull the relay. See if it disengages. If so swap the relay with maybe the horn relay, and see if it stays engaged. If not the relay is stuck and needs replaced. If it stays engaged, then move to the hvac controller.
Easiest way to find an electrical issue( for a beginner) is start furthest from the power source and work backwards.

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Good advice, thank you.

Okay and if the clutch is still engaged when I remove any power to it, then I can pretty much assume it’s damaged/stuck, right?

Not to say I don’t also have an electrical issue also, I just want to be sure I’m addressing both if needed.

Yeah if it stays engaged with no power and has enough pressure to turn the compressor it has probably welded itself together.