So I used my sanden compressor for OBA in my old xj and had it wired to a pressure switch but a lot of the time the clutch on the compressor wouldn't engage so I got mad one day and hit it and it worked then found out if you push it over with a screwdriver a bit it would engage it but only when theres power to it I think so I thought it was just the clutch was sticky or something then I went to put OBA into my new xj and it does the same damn thing do I just have bad luck with the clutches or is this some wiring thing

 

Its just the clutch is out of adjustment. When it gets power its an electromagnet and pulls the clutch closed