I have had problems with my a/c compressor not coming on at all unless it is wired directly to 12 volts. Relays, fuses, and switches are all good. Had someone tell me that the only thing else he thinks it could be is a bad PCM module. Can I replace the PCM module with another one from a wrecked truck of the same year model? And if so, do I need to have it flashed before putting it in my truck? Also, if I do put in a replacement, will the odometer reading change to that of the truck I stole the PCM replacement from?

 

Some one else is telling you it could be plenty beside PCM (very remote). Get a FSM and you'll see. Fill out signature for year, although 24 v are similiar wired. Your add on goodies could even be affecting the AC.

 

Its a 2002 3500. What do you mean by FSM?

 

Factory Service Manual

 

So you wouldn't think it's the PCM? What else could it be? All freon is at proper levels...fuses and relays are good...Inside switch is good...Just no power to the compressor.