I have a 97 Cavalier and just did an evac and recharge on my a/c but the clutch wont pull in. I have checked out the relay and the clutch and when I jumper the relay connections, Wahlah cold air.
To those of you that have seen my earlier post on what I was dong to this car you should know its now finished and driving and this is my only issue.
But as a quick recap, I bought a 97 Z24 and yanked the engine tranny and harness out of it and replaced it with a 2.2 engine and standard tranny.
The engine runs great and the tranny is solid, nothing else seems to be of issue except for the A/C.

Here is what I have checked.

The clutch ohms out and is good
Same for the clutch relay
Jumper pased the relay and the clutch works
Tested for voltage at the relay and 12.5 is present but the relay does not pull in.
Checked for broken loose and disconnected wires and have not found any. Traced them all the way back to the ecm.
Tested the wires to the pressure switch but got no voltage to ground or across the terminals.

I know that all the information goes through the ecm to make it work but I am curious, since I am getting voltage at the relay it should be pulling in and turning on the compressor clutch but it is not. Is there a diode or something that controlls the durrent being supplied to the relay that is not letting it pull in? Does anyone know the sequence of events for the clutchto pull in?

Here is what I think is supposed to happen and what actually does happen. The switch for the a/c is turned. the computer checks the pressure switch and looks for a positive responce (not sure if this is happening or not), after this the cooling fan kicks on (this is happening) and the engine idle kicks up (not happening). After positive feedback from all these events 9Mixed emotions here) the signal is sent to the clutch relay (have voltage there) and pulls in the clutch ( not happening). Please correct me on any errors here and advise where to look next.

Any help would be greatly appreciated.


I may be Crazy but I think this will work....Naw I'm just crazy.

It is possible that you put in to much freon and the high pressure switch will not energize the system. So when you bypass that system it turns on...

the grey wire at the high pressure switch is the 5v ref wire and should have voltage. If you don't have voltage there there will be no signal back to the ecm; the ecm will think the system is empty or too full (i not sure which) and withhold the a/c request...not ground the a/c relay.