I have been told that it is difficult to get to the snap ring on the clutch pulley for this car, so I will probably take the whole compressor off and deal with it off the car. Should I be getting voltage to the three-terminal harness going to it?

__________________
1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles