RAM 3500 Truck 2WD L6-5.9L DSL Turbo (2008)
Compressor Clutch: Description and Operation
Operation
OPERATION
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 assembly.
A/C compressor clutch engagement is controlled by the powertrain control module (PCM) or the engine control module (ECM), depending on engine
application. When the A/C-heater control is set to any A/C position, it sends a request signal on the CAN-B bus to the totally integrated power module
(TIPM), which then transfers the request on the CAN-C Bus to the PCM/ECM, which determines if operating conditions are correct for A/C clutch
engagement. When all operating conditions have been met, the PCM/ECM sends a signal on a dedicated hard-wired circuit back to the totally integrated
power module (TIPM) to energize the internal A/C clutch high side driver. When energized, the A/C clutch high side driver provides battery current to
the A/C clutch field coil.
The A/C clutch control system is diagnosed using a scan tool.
The A/C compressor clutch components cannot be adjusted or repaired and must be replaced if found inoperative or damaged.
