I just bought a used 2004 Ford Ranger where the AC compressor will not turn off. With the the climate controls in the off position the AC compressor will run. I have to un plug the compressor for it not to run. If I leave it plugged in overnight it will kill the battery. The unit pumps out ice cold air.
I am a refrigeration technician so I am pretty good with a meter and a set of guages. I will buy an AUTO AC adaptors to hook up to my guages if I need to.
When the truck is off with no key in the ignition and I unplug the copressor I will hear some kind of solenoid clicking.