So last summer I realized the JK AC stopped working. We didn't worry until we were on JJ and sitting idling for some time got pretty warm in the Jeep. It had worked earlier in the year before we did alot of work to it. I had removed all the interior and sprayed with raptor liner. Also did alot of cleaning under the hood over the summer.

Anyway when I noticed it not cooling I assumed it was low on freon so grabbed my gauges and hooked them up one afternoon. The AC shows charged yet the pump will not turn on. I checked all fuses and did alot of testing for voltages and such. Nothing really jumped out. Light turns on with button on ahs but no compressor. Last thing i did was jumper 12V to the clutch and the compressor turned on and started to cool however got smoke from clutch so unplugged. I plan to order a new compressor and pressure switch next week but is there any oter things I should check first. I would think some how i should get some 12V power to the clutch plug when i turn on the switch but unless my meter is wrong I never see any real voltage. Does anyone have a manual that shows what I should see there ? I have no issues grabbing a compressor as the Jeep has 180K on it anyway but hate to order it if there are other issues.

 

If you leave the compressor running too long it will reach a pressure quickly where it will lock up in over pressure so be careful there. Reaches pressures over 400PSI. Ever hear a unit running in the summer - hear clutch on and off every 5 seconds or so.
Attached is the 2008 AC clutch diagram from the TIPM. Mine was working and quit. Ignore the blue as that is part of the Chev conversion to Jeep. Uses Chev compressor wired through Jeep system.

 

Thanks. I never noticed high pressure with it on but only had it jumped for a few minutes. I mainly wanted it on to make sure my freon was correct. Thanks for the diagram. I'll keep digging into it.

 

So wanted to follow up on this. today I had some time so decided to do some more testing. Again I had voltage bouncing on the GN wire. I then measured the black to ground. Nothing. Test light wouldn't light and ohm meter showed no ground. I grabbed an aligator jumper, hooked to ground stub on fender and clipped on black wire and AC came to life. Ran for 30 minutes and was cold as cold.

So it appears I lost the ground. I had read someplace the ground terminates someplace near the back of the engine possibly ? Anyone know where it really goes ? I may just run a new ground from the fender stud to the AC and tap the ground so what ever else is on that circuit has a ground.

 

To finish this off. I tried to figure out where the ground was from and after 3 hours just ran a new ground. It works great at this point.

 

Thanks for following up! It's frustrating when some come to the forum looking for help and then figure out the problem and never report back the fix. Then when I go looking to fix my problem, never find any answers.