I have a 94 Z28 and this afternoon, the AC stopped working. The compressor clutch does not engage when I turn on the AC. I have checked the AC fuse in the dash, and the AC fuse and relay under the hood. All are fine. I hooked up a gauge to the low pressure side of the system with the AC off and I got around 120psi. I can't tell what the pressure on the low side would be with the AC on because the compressor won't engage.
I don't have my laptop and cable with me so I haven't scanned it to see if there are any codes.
What should I check next? The AC was working fine this morning.
Thanks,
Steve

 

Check the relay?

 

Yes, I checked the Relay under the hood... I even switched it out with the one for the fog lights since they are the same part number... The relay seems to be workng correctly.

 

Low pressure switch???

 

I guess the low pressure switch is a possibility... How can I test it?
Thanks,
Steve

 

I have the exact same problem. Clutch isn't engaging. I know its gotta be a sensor, but which one???

 

LOL, same problem here. Its a conspiracy I tell ya. Im guessing its the low pressure switch also. I havent scanned mine yet either. Was working great, then one day nothing, compressor isnt kicking on. Gotta scan and see if the PCM is commanding it on or not. If it turns out to be the switch,.....is there a way to change it out without purging the system, or will you lose your freon when you pull the switch? Is it possible to change it out fast enough with a pair of gloves on so not to burn yourself?

 

just unscrew it, it is on a shrader valve

 

I just scanned my pcm and it had a code 61. I cleared the code and then the compressorwould engage. I was on the low side of the pressure scale ~35psi in 95f+ heat and 80% humidity. I added some r134a to get it close to 40psi on the low side. now everything seems to be working fine... I'll keep an eye on the situation and see if it happens again. then I might suspect the pressure switch is bad, but I'm guessing that the pressure spiked a little low and tripped the code.

Thanks for your help and to the other guys having the same problem, get access to a scanner and it should let you know what's going on...

Steve

 

the low pressure switch wont engage the compressor if you dont have enough refrigerant in the system. You probably have a leak somewhere, and lost enough refrigerant to trip the low pressure switch.

Find the leak and recharge it, you have to jump the compressor to get it to engage when you fill it.

 

BTW, mine suddenly started working. Hooked up the laptop, scanned the pcm and now its fine. ??????

 

just unhook the pos side of bat for 15 min to reset computer then try worked for me ..