HELP! A/C Compressor/Clutch not turning on...

[Achilles99]

My A/C isn't blowing cold, and a few of the Viper guys here noticed that my AC clutch wasn't activating. Is there a fuse or something I can check? I've checked the A/C relay using someone else's car as a test, and it seems fine. Is there an electrical harness/plug somewhere I need to plug in that might might come unplugged by accident?

Thanks in advance!

 

[Jack B]

Achilles:

I have the same problem and did some research, basically bypass (Shunt) the high/low pressure switch (passenger side under air box)with the engine running and a/c on. There is an relay on top of the PCM that picks up the signal from the the high/low pressure switch, activates the relay and sends 12 volts to the compressor.

Check for the 12 volts with the pressure switch bypassed, to see if you get the relay to close. If the relay closes it has to be a bad compressor. The compressor has a two wire connector, 12V from the relay and a wire that goes to ground. The ground connection could be bad, or the compressor is the problem.

If you get the compressor to pick up, then, remove the jumper on the high/low pressure switch, if the compressor will not energize, it is a problem related to the pressure switch or refrigerant.

 

[Achilles99]

Jack:

Thanks for the response. So, you are saying to connect a wire across the high/low pressure switch leads, right? How do you know if the relay closes? By checking for 12 volts? If so, which wire should I be checking for 12 volts from? The one on the compressor?

Thanks! Car has a Maxcare warranty on it, but I was trying to see if there was a quick fix I could do at home. Getting to the A/C compressor seems tough... do you do it from underneath the car, or from the top?