Compressor HVAC: Description and Operation

NOTE:
^ Internal A/C compressor components are not serviced separately. The A/C compressor is serviced only as an assembly. The A/C clutch, A/C clutch pulley, and the A/C clutch field coil are serviceable.
^ Whenever a new A/C compressor is installed due to a failure that produces foreign material in the system, also install a new suction accumulator/drier and A/C evaporator core orifice.

The A/C compressor has the following characteristics:
^ A seven-cylinder wobble-plate design.
^ Seven pistons operate within the cylinder assembly. The pistons are actuated by a wobble-plate clutch assembly.
^ Reed-type discharge valves are located between the cylinder assembly and the head at the rear of the A/C compressor.
^ The A/C compressor uses Heavy Truck PAG Oil or equivalent. This oil contains special additives required for the A/C compressor.

Compressor Clutch Components:

The magnetic A/C clutch has the following characteristics:
^ It drives the compressor shaft.
^ When battery positive voltage (B+) is applied to the A/C clutch field coil, the clutch plate and hub assembly is drawn toward the A/C clutch pulley.
^ The magnetic force locks the clutch plate and hub assembly and the A/C clutch together as one unit, causing the compressor shaft to rotate.
^ When B+ is removed from the A/C clutch field coil, springs in the clutch plate and hub assembly move the clutch plate away from the A/C clutch pulley.