VehiCROSS 4WD V6-3.5L (1999)
Compressor Clutch: Initial Inspection and Diagnostic Overview
Inspection and Repair
Drive Plate
If the frictional surface shows signs of damage due to excessive heat, the drive plate and pulley should be replaced.
Pulley Assembly
Check the appearance of the pulley assembly. If the frictional surface of the pulley shows signs of excessive grooving due to slippage, both the pulley
and drive plate should be replaced. The frictional surfaces of the pulley assembly should be cleaned with a suitable solvent before reinstallation.
Coil
Check coil for loose connector or cracked insulation.
A/C Clutch Control Circuit Diagnosis
A/C Clutch Control Circuit Diagnosis
Circuit Description
When air conditioning and blower tan are selected, and if the system has a sufficient refrigerant charge, a 12-volt signal is supplied to the A/C request
input of the powertrain control module (PCM). The A/C request signal may be temporarily canceled during system operation by the electronic
thermostat in the evaporator case. The electronic thermostat may intermittently remove the control circuit ground for the A/C thermostat relay to
prevent the evaporator from forming ice. When the A/C request signal is received by the PCM, the PCM supplies a ground from the compressor clutch
relay if the engine operating conditions are within acceptable ranges. With the A/C compressor relay energized, voltage is supplied to the compressor
clutch coil.
The PCM will enable the compressor clutch to engage whenever A/C has been selected with the engine running, unless any of the following conditions
are present:
-
The throttle is greater than 90%.
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The ignition voltage is below 10.5 Volts.
