Just changed R4 compressor, accumulator and orifice tube and flushed. Pulled a vac for 3 hours and it held rock solid for 20 hours so I charged her up and have nice cold air. While trying to swap the fan cutout switch from my old comp to the new it cracked and became unuseable due to very brittle plastic. Ordered a new one and it came with a different style plug so I had to splice it on. Problem is now my radiator fan runs anytime the key is in run. Also the compressor clutch will engage with the engine off and key in run if ac is selected. It never did either of these before. The fan would run when the ac was turned on and shut off when ac was selected off unless the engine was still hot and the water temp switches kept it running. I have 12 volts to the switch any time the key is in run whether the engine is running or not. I think I heard this switch operates at 150 psi. Does that mean it should only come on when the ac is selected on? I have continuity through it with the engine not running so shouldnt the pressure in the comp be less than 150 psi? I think I put a switch on that is stuck in the closed position and it cost me $26.00 and now probably 2.75lbs of R12 to have it removed for troubleshooting!! Anyone know if this is a normally closed or normally open switch and know its working pressure?

 

Sorry it is an 84 Corvette

 

The A/C fan switch screws into the back of the compressor. The GM part number is 2724279. AC Delco# 15-2235. For the C4s, it is a 1984, only, set up.

RACE ON!!!

 

thanks, I'll go back to the part store and make sure I got the right switch.