# A/C Clutch not engaging??



## chiefwahoo (Feb 27, 2010)

I found that the a/c clutch isn't engaging. I had freon hooked up thinking that it was low or out of freon. The clutch still didn't engage. I looked in the fuse box for a fuse, but to my supprise there is no fuse for the a/c. I thought there was maybe a relay, but when I called my local Audi dealer parts dept. they informed me that their computers didn't show a relay either. I know that there has to be something in the wiring system that could possibly keep the clutch from engaging.
Please help.


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## Mawrick (Jun 26, 2004)

not sure about the Audi - but on my Corrado there isn't any relay inside the car at least - but AFAIK it's somehow controlled by the fan controll module.

it also have an ambient temp sensor that could cause it to fail. However I would presume you could try to "jump" the clutch just to make sure that it actually works by supplying 12V to it - IF it works the same way as on my car......


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## chiefwahoo (Feb 27, 2010)

*Update*

I jumped the a/c clutch and it engaged. So now I know it's not getting a signal to engage. 
When I had the clutch engaged and engine running, the low side was around 50-60 psi. I don't know what the optimum pressure is because when I worked on auto a/c it was r-12. I would appreciate any feedback on that also.
My inside air to outside air is only around a 20 degree drop.


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## Mawrick (Jun 26, 2004)

chiefwahoo said:


> I jumped the a/c clutch and it engaged. So now I know it's not getting a signal to engage.
> When I had the clutch engaged and engine running, the low side was around 50-60 psi. I don't know what the optimum pressure is because when I worked on auto a/c it was r-12. I would appreciate any feedback on that also.
> My inside air to outside air is only around a 20 degree drop.



Not sure about that pressure sorry - at least on my system one could also jump the wires on the pressure control switch (not sure if it's the same on yours though) to see if it will feed 12V out to the clutch.


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