Hey guys I'm new here but I recently bought a,1988 Jeep Cherokee and the AC clutch doesn't pull in but if I jump it it pulls in and runs . I jumped the low pressure switch and it seems good. I can't find the high pressure cutoff switch , id like to test it as well. Also the auxiliary fan wasn't working when I jumped it. So I ordered a new one I don't know if a bad fan would prevent the AC from working. Also I checked all four of those relays on the passenger wheel well they were all good. Is there another relay somewhere or another connection I should check? All the fuses are good.

 

Check a diagram and make sure you have all your relays and fuses.

Did you check the connections in the wiring harness? Trace the wires and at every connector, open it up, clean it with CRC electrical parts cleaner or similar, dielectric grease for all the pins, and silicone spray for the gasket.

 

Recently had a similar issue, but I couldn't get the clutch to engage even jumping the pressure switch. Turned out to be a the relay. I'd start there since that's pretty simple.

Good luck

 

Which relays? All four of those sqare ones on top of the wheel well are good.

 

Under hood passenger side, there is an a/c fuse in there too iirc

 

Correct.

I almost didn't bother swapping mine because I was getting some voltage, just not enough to pull the clutch in. I had some spare, cheap, "aftermarket" (team grand cherokee micro relay) relays kicking around anyway and was shocked when all of a sudden my problem went away. I then bought a used original Siemens relay from the auction site, just because.

Good luck