A/C Compressor Clutch: Operation

WARNING: This page is about a different car, the 2005 Dodge Stratus and 2005 Chrysler Sebring. However, it is still accessible from the selected car via links, so may be relevant.

The A/C compressor clutch components provide the means to engage and disengage the A/C compressor from the engine accessory drive belt. When the electromagnetic A/C clutch field coil is energized, it magnetically draws the clutch plate into contact with the clutch pulley and drives the compressor shaft. When the coil is not energized, the pulley freewheels on the clutch hub bearing, which is part of the pulley.

A zener diode is connected in parallel with the A/C clutch field coil. This diode controls the dissipation of voltage induced into the coil windings by the collapsing of the electromagnetic fields that occurs when the compressor clutch is disengaged. The zener diode dissipates this induced voltage by regulating a current path to ground. This arrangement serves to protect other circuits and components from potentially damaging voltage spikes in the vehicle electrical system that might occur if the voltage induced in the clutch coil windings could not be dissipated.

A/C-heater control in the passenger compartment
A/C pressure transducer on the A/C discharge line
Powertrain control module (PCM) in the engine compartment
A/C clutch relay in the power distribution center (PDC)
Models equipped the 2.0L and 2.4L Turbo engine also use a thermal limiter switch mounted to the A/C compressor to disengage the clutch if compressor surface temperatures become excessive.

The A/C compressor clutch components cannot be repaired and, if faulty or damaged, they must be replaced.