A/C Is Always On Or Compressor Runs Continuously

WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2002 Mazda Tribute, 2002 Mazda Protege5, 2002 Mazda Protege, 2002 Mazda Millenia, and 2002 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.

Stuck engagement.
A/C pressure switch stuck closed.
A/C relay is stuck closed.
Short to ground between A/C switch and PCM.
Short to ground between A/C relay and PCM.
A/C relay to magnetic clutch circuit short to battery power.