RAM 2500 Truck 4WD L6-5.9L DSL Turbo VIN 6 (1999)
Compressor Clutch: Description and Operation
Clutch Control = relay = PCM
SYSTEM OPERATION
Compressor Clutch - Typical
The compressor clutch assembly consists of a stationary electromagnetic coil, a hub bearing and pulley assembly, and a clutch plate. 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.
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 low pressure cycling clutch
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.