Minimum Compressor on Time
Minimum Compressor On TimeVehicles operating above 32 km (20 MPH) will be controlled to a minimum ON time of 4 to 6 seconds before the DIM will allow the clutch to disengage. After the minimum ON time has expired the DIM will request the PCM to disengage the compressor clutch only if the low side temperature is below -2°C (28°F). After reaching this turn off temperature, the DIM waits for the low side to reach a turn-on temperature of 10°C (50°F) and then repeats the cycle. During the compressor on cycle any of the following conditions will force the PCM to disengage the clutch:
^ Battery voltage low.
^ A/C Pressure Sensor detects a low or high pressure condition.
^ Coolant temperature above 126°C (259°F).
Except for the wide open throttle, all of the above conditions will keep the compressor OFF until the condition no longer exists. The wide open throttle condition will keep the compressor OFF for a maximum of 20 seconds.
On initial crank the DIM will check for indications of liquid refrigerant which may have collected at the compressor and if found, the A/C clutch will engage. After the engine is started, the clutch will disengage and waits for normal conditions to re-engage of the clutch.
If the conditions are not met for engaging the compressor, a service A/C system message will appear on the driver's information center.