A/C prob - no power at relay, comp doesnt start

Engine: 3.4L DOHC:banghead:
Problem: Air Conditioning doesn't work

Info: No power at A/C compressor relay in underhood box. All fuses in glove box are fine. Anyone know where the other relays are? Then manual says under the instrument panel. I haven't looked yet, but I hope I don't have to disassemble anything to get to it.

Please Help! I like air conditioning, and I'd like to sell the car at some point.

I was thinking about selling my 92 GP SE 3.4L for a 97 Talon TSI? Good idea?

Any help with the A/C would be great.

-Dan

There may be a leak in the system and the refrigerant has all leaked out. The computer tells the compressor not to run if no refrigerant is present. If you can find the valve where refrigerant is put into the system-looks like a valve stem on a wheel-take the cap off and give the pin a quick push with a pen or something. You should get a blast of freon. If not then its time for a dye test to find out where the leak is.

Thanks for the suggestion. I didn't think to check the Freon level because I didn't know the compressor wouldn't run if the system was empty. I just assumed the problem was electrical. I hope there isn't a leak. It was just retrofitted to accept R134.

I'll go do that now. Any suggestions if there is Freon in there?

OK, I did what you said...pushed the little button...I wouldn't call it a burst of freon, but I got a little. Seems like very low pressure so maybe there is a leak. Damn.

You need to most likely replace the ambient air sensor, located in front of the radiator...a 2" black plastic item about half the size of a pen. Costs about 8$ at a dealer (only) It will not allow your ac compressor to operate if it reads cold (33-44) outside air. If you are seeing those numbers on your a/c controls, just replace it, that is the cheapist fix going....sadly after thousands of miles of hot driving and more than a 100$ of other parts, thats what fixed it.
Good luck
Dubbster

If the system pressure is good, then you need to replace the low-side pressure switch. This switch grounds the compressor clutch when pressure is detected, if it's bad, the clutch doesn't ground and will cause the air not to work. You can test it by unplugging the switch and putting a jumper across the pigtail. If the compressor kicks in, the switch is bad, if not (assuming the system has enough refrigerant) teh clutch switch on the compressor is faulty.

Don't know that much about the 1992's But do they have a electrical center like the 1997-2002? If so, check for fuse there. And you don't have power at either side of the switch? I like to check the cheap things first.
Good luck
http://img.photobucket.com/albums/v425/kustomkid54/1998PontiacGrandPrixGTP004.jpg

The low level is one reason, if the expantion valve fails to open is other reason. If the car was a a late Eclipse(Talon) before the V6 then a lot of aftermarket performance parts if not then don't even bother.