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Chris (aka-Moose)
Chris (aka-Moose), Technician
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Experience:  16 years of experience
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Buick Rendezvous Ultra: I have a 2005 buick rendezvous. The

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I have a 2005 buick rendezvous. The A/C works but compressor runs off and on - it acts like thermostat is not reading the temperature in the cabin or something.
I am wondering if it may be a control panel issue, pressure switch or maybe A/C clutch? It will cycle on every 5-10 minutes for about 5-10 minutes, then it is just vent temperature air.

Hello, I'm Chris. Thanks for visiting Just Answer.



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Customer: replied 3 years ago.

Thanks for the reply Chris.


So here is what I know (or think I know).


I am confident it is not a compressor issue or Freon issue as when the A/C is "on", it is nice and cold. For some reason, all of the sudden, the A/C developed this issue where the A/C won't run consistently as needed. Some days it will work for longer periods of time, then is it just vent air without any A/C, then the A/C will kick back on for a short time. There doesn't seem to be a definable period that the A/C will run.


It "acts" like the climate control thermostat is not working properly - as if it is not sending a signal to engage/disengage the clutch.


No matter where I set the temperature or play with the climate controls, I can not keep the A/C running dependably for any length of time.


The condenser is clean, the freon and compressor seems to be fine because it is cold when the system is engaged. So I wonder if it sounds more like a pressure switch or control panel issue? (or something else)

We need to start by ruling out a weak compressor clutch by checking to see if there is power commanded to the clutch when the compressor should be running but is not. See the diagrams below

The power wire is the dark green wire.


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