a/c compressor not working

[007monkey]

Trying to figure out the problem on my a/c. When I press the a/c button in the compressor doesnt kick on. So I checked to make sure all the visible connections in the engine compartment were ok and they seemed fine. I checked all the fuses, the seemed fine too. So I happened to check the a/c relay in the engine fusebox. I was using my test light, with ground attached to neg side of battery, to see what had power and what didnt. When I pulled the relay out to where the contacts were just touching and I could get my test light in there, I touched the bottom right contact on the relay and the compressor kicked on(bottom right if you are on driver side looking at the relay). Figured it was maybe the relay so I bought one and same thing happened, it only works if I touch the contact. Any ideas on where to start? Thanks.

[HowieE]

The first thing I would do is pull the connector off the Low Pressure Switch located on the Accumulator, silver can forward of the passanger side firewall, and jumper that connector with a paper clip. If the compressor cycles you are more than likely low on Ref., possibly a bad switch, but more likely low ref. If the compressor does not come on when you jumper out the connector test for voltage on the input side of the connector, Light Green wire. If you do not have voltage there check the Htr AC fuse in the IP fuse block. If you have voltage on the Light Green wire check for voltage along the Dark Green wire coming off the Low Pressure switch to both side of the High Pressure switch, located on the manifold at the compressor.
If you have voltage on both sides of the High Pressure switch the control side of the circuit is good.
If nothing has solved it at this point. Try and get to the underside of the relay socket and check the wire color that leads to the point you are grounding out the relay. If that wire is Dark Green/White and grounding it cause the comperssor to come on it looks like the problem is in the PCM. Rather than buy a new PCM I would cut one of these wires at the PCM. Dark Green wires at location C2 on connector C1 or D5 on connector C3 at the PCM. Take the cut end coming to the PCM and jumper it to the other wire. If this solves it the problem is in the PCM.
I suspect the problem will be low ref. or a bad low pressure switch, that the common area.

[007monkey]

Thanks for the advice.
OK just checked all the connectors. I jumpered the low pressure connector and got nothing. So I started pulling off the connectors and found that none have power on either side of them. Even with the low pres and high pres disconnected I can still ground the relay to get it working. Is this pointing me toward a pcm problem? Or should I still check the pressure or have it recharged? My train of thought tells me that since nothing happened when I jumped the low press connector then it must not be the pressure of the system...
EDIT: OK just figured it out. The dang ac button is the cause. I pressed it in real hard and moved it around a bit with finger on it and the compressor comes on and ac works. Gonna try a toothpick in the side of it and see if that works for now until I can get at the switch. Will have to search the site for info on replacing that, it doesnt look like fun though. Thanks again.

[ 07-13-2004, 12:04 PM: Message edited by: 007monkey ]