ok, so heres the thing, I just had my AC system replaced and converted to the new refrigerant R134a. the system has been charged, and everything is set up to work fine, but the compressor wont turn on unless you run power straight from the battery. I've gone through all the troubleshooting guides from the mechanics guides. and the only thing that isnt testing correctly is the alternator signal. its supposed to test w/ less than 1 volt while the engine is running. however while the engine is running I get system voltage on this signal wire. when the engine is off but the key is in the ON position I finally get the less than 1 volt reading. any ideas about whats goin on??

 

I think that you need to do more research on your AC system, the AC Compressor gets a signal from the AC Compressor relay and it get a signal from the AC Amp (computer). There are times when the AC will not work and I am sure that you do not have this condition but there may be a malfunction. It should not work when the engine is overheating or when you are in WOT (hauling ***).

When you have a better wire diagram you can test the relay and work back to the amp. There are fuses involved, maybe more relays, the fans, pressure switches, actual pressure in the system.

 

I've been doing a LOT of research on the AC system... I found a full copy of the shop manuals and found a complete wiring schematic that I'm going to try to include in this post. here's a link to the schematic I have. http://hometown.aol.com/arctic...OL_US
and according to all the troubleshooting guides I've found everything checks out across the board except for the wht/blu wire markes as the alternator signal. its supposed to have <1volt running through it when the engine is running. I can only get that when the engine is off, but the key is in the on position. while the engine is running I'm getting system voltage. The guide suggests that there may be a break in the wire from the CCU to the alternator, but I verified that there is contenuity from the CCU all the way to the alternator. Even 2 different mechanics have not been able to figure it out.