A/C clutch always engaged

A switch like h/p or l/p is bad. Something is telling comp to run. Unplug comp and use test light. Freon and comp both have oil that is now missing.

Bottom line is you have to find signal to comp. Start with pressure switches then move to sleeper ( has sleeper right? ) . Check everything , be looking for discolored wires ( shorts) burn connections etc.

Good hunting

 

What truck? Is the dash control off when this occurs?

 

No... lp switch on big line or drier, hp switch will be on little line if it has one. FYI on newer KW nothing works in a/c without air. Kw figures w.o air then clutch fan can't engage and system will over pressure.

Unplug both switches and see if test light lights up at comp. ( member I said dont run it w/o freon ) be a quick way to eliminate these guys. Also make sure dash control is not on defrost, that will call for comp to dehumidify but that's another issue.

Test those switches one at a time and see what you have.

 

Check the compressor relay