2001 Alero 3.4, bad PCM?

[jayjw]

Recently my AC stopped working, I thought I had a bad ac clutch, so I replaced and still nothing. I went through all the fuses, relays, even the diode, all checked out ok. Freon pressure is good. I also noticed that both cooling fans are coming on seconds after start up. Every thing keeps leading me back to the control module. Also in the last month or two my temp. gauge in dash has been off and on, starting to think it might all be related.

Thanks to anyone that can lend some advice, or has had similar experience and can let me know what the outcome might be.

[BNaylor]

Welcome to AF.

So are you saying the A/C clutch is not engaging? The PCM supplies the ground (low) to the A/C clutch relay so check to see if the relay is energizing. Also you can jump the contacts of the A/C clutch relay at the relay socket and then see if you can get the clutch to engage.

[jayjw]

Yea the clutch is not engaging. Tried jumping the contacts at the socket and still nothing. When checking power at the socket we only got a reading of 5 (volts ? not good at electrical) very dim light on the tester. Thanks for your help, I usually can diagnose and fix most problems I have come across in the pass with the help of the chiltons manual, but this one has me stumped.

[jayjw]

Have an update, took it to a mechanic and he diagnosed it as a bad Body Control Module. He said I have to take it to a dealership because a new one would have to be programed. Is that the case in your experience, if I find a used one on ebay for the same model, engine, etc. could I plug it in and have it function, or am I stuck going to the dealership? Thanks again.