In my 98' the a/c compressor works when I jump power to the clutch, But no other time. I checked pressure It is around 65. In the green on those fill guages. 134a. I tried jumping out the pressure switch connectors with paper clips and got nothing. I dont know if I should not have jumped out the high side though. I will try again. I have power going to the relay, and I changed it anyway. I also jumped out #3,#5 on the socket. Also tried putting + power directly to #3 and #5. Worked last year. Any thoughts?

ok, update. Verified 12v present at #1, #2 on relay to pull it in when A/C is turned on. Wonderng if the relay switches a ground between #3 and #5 ? I get continuity between #3 and ground on the relay socket. I jumped that out with a wire to be sure and still nothing. Also I checked for continuity on my high and low pressure switches. And they are both in the closed position. (o ohms) I know I have freon charge or they wouldnt have closed. I checked wiring and everything apperas fine. Any further help would be appreciated.

http://http://www.dieseltruckresource.com/pics/search.php?keywords=IMAGE_057Ok, another update: What is this little round thing under my lines? It is on the back of the compressor. I tested 13.8v to the connector to the clutch. But it still doesnt engage. I am thinking the little round thingy is messed up. When I apply power directly to the wires on the clutch itself It engages.

well, bypassed the round thing on the back of compressor. Not sure what it was. Have normal operation now.

nice chattin with ya'll. :)

Glad we could help

Wow, great conversation at least! Nice work!

Still want to know what the round thing with wires going into it is on the back of my compressorhttp://www.dieseltruckresource.com/pics/data/500/medium/IMAGE_057.jpg