Compressor clutch. Compressor clutch relay

Compressor clutch

DESCRIPTION

The compressor clutch assembly consists of a stationary electromagnetic coil, a hub bearing and pulley assembly, and a clutch plate (Fig. 3). The electromagnetic coil unit and the hub bearing and pulley assembly are each retained on the nose of the compressor front housing with snap rings. The clutch plate is mounted to the compressor shaft and secured with a nut.

Fig. 3 Compressor Clutch - Typical

1 - CLUTCH PLATE

2 - SHAFT KEY

3 - PULLEY

4 - COIL

5 - CLUTCH SHIMS

6 - SNAP RING

7 - SNAP RING

OPERATION

These components provide the means to engage and disengage the compressor from the engine serpentine accessory drive belt. When the clutch coil is  energized, it magnetically draws the clutch into contact with the 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.

The compressor clutch and coil are the only serviced parts on the compressor.

The compressor clutch engagement is controlled by several components: the heater-A/C mode control switch, the electronic cycling clutch switch, the low pressure cut-off switch, the high pressure cut-off switch, the compressor clutch relay, and the Powertrain Control Module (PCM). The PCM may delay compressor clutch engagement for up to thirty seconds.

Refer to Group 14 - Fuel System for more information on the PCM controls.

Compressor clutch relay

DESCRIPTION

The compressor clutch relay is an International Standards Organization (ISO) micro-relay. The terminal designations and functions are the same as a conventional ISO relay. However, the micro-relay terminal orientation (footprint) is different, the current capacity is lower, and the relay case dimensions are smaller than those of the conventional ISO relay.

OPERATION

The compressor clutch relay is an electromechanical device that switches battery current to the compressor clutch coil when the Powertrain Control Module (PCM) grounds the coil side of the relay. The PCM responds to inputs from the heater-A/C mode control switch, the electronic cycling clutch switch, the low pressure cut-off switch, and the high pressure cut-off switch. See Compressor Clutch Relay in the Diagnosis and Testing section of this group for more information.

The compressor clutch relay is located in the Power Distribution Center (PDC) in the engine compartment.

Refer to the PDC label for relay identification and location.

The compressor clutch relay cannot be repaired and, if faulty or damaged, it must be replaced.