Does your car have closer or over 100K miles? Have you ever replace the ac
clutch pulley or bearing?
When the ac
clutch pulley bearing goes bad (you might get 100K miles before it dies), if you don't replace the ac
clutch pulley immediately, the pulley will wobble whenever the engine is running, and it will make contact with the ac
clutch coil ruining (damaging the windings) shorting it out.
At that point you will need to replace the ac
clutch set (magnetic plate, ac
clutch pulley, and ac
clutch coil) or the complete ac
compressor with clutch set.
You can check the ac
clutch pulley bearing with the compressor in the car by removing the serpentine belt, giving the pulley a spin, and observing what happens. If it grinding, or is loose, or spins freely, or spins canted, or wobbles, then the bearing is bad, and you need a new clutch pulley. If you can see or feel it hitting something, then you waited too long, and the ac
clutch coil is ruined as well.
If the pulley spins true, and smooth with a little drag (that should be the grease inside of bearing), then the clutch pulley should be okay.
The flat plate on front of the ac
clutch pulley is the magentic plate. It moves in and out when the ac
clutch coil is energizes to engage the ac
compressor. If the gap/clearance between back of the magnetic plate and the front of the ac
clutch pulley is/becomes too large, then when the ac
clutch coil is energized, the magnetic plate may not move to engage the ac
There is a spec for the magnetic plate clearance. If I remember correctly it is between .015" and .030". Some people have suggested using a broomstick while the engine is running with the ac
switched on to push the magnetic plate towards the ac
pulley to see if you can force the magnetic plate to engage the ac
clutch pulley. This may prove that everything is working, but that the magnetic plate clearance needs to be reset.
You need to buy an ac
manifold gauge set if you are serious about working on your ac
system. The little gauges that come on refrigerant cans is a joke.