Ok, I don't know what else to do. I've searched the forum and stil can't figure it out. My ac clutch went out. New ac pump installed and all that good stuff, worked for about a month then the pump leaked. So returned it and got a new one. Then the pressure cut off switch sent out so I got a new one. Worked, but now the ac pump isn't engaging again. The system has pressure but the clutch won't engage again. Fuse under dash is good so what else is there? When I first changed the pressure switch it worked fine as I charged the system but a few hours later I got in my car and noticed it wasn't engaging again. Any ideas? It's hot here in California and would really appreciate some ideas. When the switch went out it wouldn't allow power to the pump and it's acting like that again. Turn ac on and the pump won't engage.

 

Oh and it's a 1997 Honda Civic LX

 

Unplug pressure switch and use ohm meter to confirm it is closed circuit. If not, check the pressure.

Does the condenser fan come on when you press the A/C button?

If fan starts and engine revs up but the compressor doesn't engage, due to no power, the compressor relay could be bad. It should be in the underhood fuse box. Swap it with the defogger relay from the same box, they're the same type relay.

You can jump the compressor wire to the battery with the ENGINE OFF to see if the clutch pulls in. DO NOT jump the compressor with the engine running-- the condenser fan won't be running which will lead to a severe over-pressure situation.

 

Jumped the pressure switch and clutch engages, all relays are good, but found that it was low on freon. Now I charged it back up but the funny thing is that when I was charging it, it wouldn't get cold even though the freon was entering the system. Now what is the possibility of the dryer can leaking? Or the condesor? I don't notice a leak around them and I didn't really notice a leak during the test. Is it possible I still have air in my lines?

 

Obviously there is a rather major leak somewhere. The best way to find these is to put in a small amount of refrigerant (with the engine off) and sniff around with an electronic leak detector.

Also look for oily spots especially around connections. If the oil has yellow / green dye in it, that is for leak detection-- the dye will really light up under a black light with the car in the dark. With pressure in the lines, soapy water will bubble up when applied to a leak. The relief valve on the back of the compressor (underneath a heat shield plate) may have opened and failed to re-seal fully.

After taking a line apart to make repairs, you must use a vacuum pump to remove air before charging. Air in the lines will cause poor performance, not the problem you are experiencing.

 

I guessed I have a leak. I have all the equipment to fix ac systems I just can't find the leak. It's not leaking around the lines because I already checked that. I used freon with dye but I have to wait until it's dark to see anything. The first time I filled it up I couldn't hear anything leaking out but within 3 hours I had no pressure in my lines. When I pumped the system down it held vacuum and stayed in the green on the gauge. Is there any common places that the system can leak out of? I thinking of just changing everything out but if it doesn't work it's a waste of money.

 

If you have all the other tools, you really should buy an electronic leak detector for situations like this. The limitation of dye is that it rides in the oil, and when the system isn't fully charged and running to make the oil splash around, a lot of leaks will only leak gas.

 

I found the leak. Turns out the new compressor I installed is defective so they are sending me a replacement. While I'm at it I want to change the oil in the system. Can anyone tell me how to fully drain the oil in the ac system?

 

Getting the oil out of the evaporator and condenser is complicated and it takes special equipment. First you have to disconnect the lines to isolate the part, which for the evaporator means taking the evaporator box out of the car. Then you need to blast solvent through (big air compressor and special equipment) and then blast a bunch of CLEAN air through to get the solvent out. I would recommend not messing with it and just replace the compressor. Be careful about having too much oil, don't put the full 4 oz in the new compressor since there is going to be at least an oz still in the other parts.