Two weeks ago, I changed the evaporator in my 95 Accord. Charged the system, everything worked fine. Had a bit of a problem with the cooling fan dying, so I changed that, too. A few days ago, I noticed that the clutch pulley (the one that freewheels when the AC is not on) was wobbling a bit and making an obscene rattling noise. Well, today it froze completely,and I had to cut the belt just to get the vehicle home. I got a 'new' compressor from a very reputable salvage yard, did the full install, changed both belts, and fired it up. The car runs fine, but the compressor does not come on at all. I know there's a chance that I got a bad part, and I have a 30 day warranty on mechanical parts, so the worst case scenario is pulling the thing out again (easier now that all the bolts are broken) and getting a new one and redoing it all. I have the charge hoses and an air compressor, so my only cost is really refrigerant and new o-rings and such. Given my experience with basic mechanics, there's always a switch somewhere that can be jumped off. I'm thinking that maybe this is my problem because the part was in really good shape, and the freewheeling pulley works like a champ. I say this because it does absolutely nothing. It doesn't cycle at all when you turn the AC on, which I know they do even if they're low on refrigerant. It does absolutely nothing. I tapped on it, checked the harness that plugs into the fan, made sure the belts are tight (not too tight) and ran it through every cycle on the AC control panel. Checked the fuse, too... I knew that was coming!
Any idea about that switch or anything that might explain why this is happening? I bought the car used and wrecked, but got such a good deal on it that it was worth some sheetmetal and paint, and a little TLC for those things that most people tend to let slide. Now the cooling system has been flushed, thermostat and some hoses changed, SRS redone, trans serviced, inside detailed and tires rotated... it's about 92 degrees here, and I NEED the AC!! HEEEEELP!

 

Turn the A/C on and pull the one wire plug going to the compressor.

That plug should have 12V when you have the A/C turned on. If you have 12V, then there is something wrong with the magnetic clutch on the compressor.