I have a 95 bonneville...not SuperCharged its my daughters car at college...appears the AC went out and the clutch broke on Compressor...Took it to local mechanic...he said he had P1640 and P1641 error codes before he replaced the compressor. Now with the replacement compressor, whenever he turns on the AC the check engine light comes on and it kills power to the AC. A P1640 error code comes up again for him. The mech says this appears to be related to QDM1. He called the local GM shop and they had no reference to this apparently.
Any thoughts on what steps to check next? He is looking at replacing the PDM module with one from a salvage yard, thinking the electrical load from the bad compressor maybe fried it.
Car has 200,000 miles on it and I just stuck new brakes and head gaskets into it, I need to keep the repairs cheap for her as she is in college.

There are usually 3 items controlled by a QDM. I forget what the three are, however searching that code or QDM here should get you the answers on what items to check.

And yes..there is a chance the pcm is bad. Should be cheap as they are only about $80 at local parts stores and take about 15 minutes to swap.