Auto Air Conditioning & Heater Repair: smoking ac compressor/clutch, compressor clutch, voltage spike

Question
I have a 94 Olds Silhouette ac not working.  I added refrigerant to it today so that the compressor would kick on.  When it did kick on, it started smoking and I could see what looked like flames or sparks behind the clutch.  I turned off the AC right away.  Do you think it is just the clutch, or does the compressor need to be replaced?  Thanks

Answer
Hey James,

Functionally speaking, most sparking comes from electricity, so there's a good chance that it's just the clutch coil. However, if the compressor has internal issues, and the clutch is fighting it, then smoke would happen as well. You could ohm test the clutch coil -- it should measure around 3 ohms. If the clutch has a diode, test that too -- it should allow current flow in one direction, and not the other -- or isolate it from the clutch test. Its existence is to cut down on the inductive voltage spike when the clutch is engaged.

You could even use a 10A fused jumper to apply the clutch, with the car off. If it is bad, the fuse will let you know. If the clutch is shorted, it really *should have* taken out a fuse in the system (it might have, actually).

Aside from that, inspect everything real good. If things were cooling just fine, then chances are you can install a new clutch, with the proper tool, of course.

Good luck!