Hey, guys. I discovered a worn spot in one of my AC lines the other day and got a recharge kit with a leak detector, but when I went to fill it, I turned the AC to MAX on the dash, but the clutch didn't engage! Can't charge without it going apparently....So then, I unplugged the single plug for it and jumped it from the positive battery terminal straight to the compressor side of the plug and it engaged! Plugged back in normally and still nothing....

I would've tried charging it while it was jumped, but the wire was getting REALLY hot REALLY fast, so I decided not to. For now, if you guys could help me track down some things to check/test so I could get it charged and try to see if that spot had leaked at all, that'd be great! I'm planning to do an onboard air system soon, so I'm not really all that conserned weather or not the lines hold pressure, just as long as I check for any other problems.

I checked the PDC under the hood and while the cover shows there should be an AC relay in there, there's not. Granted, the cover's off another year XJ, so it might not be correct. Also, the spot FOR the AC relay has the slots, but there doesn't appear to be any electrical connectors in them.

My Jeep is a 1993 XJ 2.5L with factory AC, at least I'm very sure it was factory. Doesn't appear to have been installed afterwards. Really just looking for reasons the clutch wouldn't be engaging unless jumpered is all.

 

low pressure switch is probably keeping it from engaging to protect the compressor

 

Okay, any idea where it might be and how I could test it?

 

use a heavier gauge wire for the jumper. The pressure switch will not let the compressor run with it plugged in unless there is enough pressure already in the system.

 

I'll try the heavier wire, but I still ask where the switch is? I cannot find it

 

on top of the accumulator to the left front of the engine bay, near the compressor. Unplug it and jumper the contacts of the connector. A paper clip works well.

 

Ah, perfect! I'll go out soon and try that! Thanks!

 

one of the reasons it shuts off when there is low / no pressure is that the refrigerant mixes with the oil, and that lubricates the internal parts of the compressor. When the system is low / empty, the oil doesn't get circulated and can't lube the parts, leading to part failure. Make sure if you jumper it that you quickly add the right amount of oil / refrigerant.