Pinpoint Test Q: The Air Conditioning (A/C) is Always On - A/C Mode Always Commanded ON: Notes

Refer to Manual Climate Control System for schematic and connector information.

Refer to Automatic Climate Control System for schematic and connector information.

Normal Operation and Fault Conditions 

An accurate evaporator temperature is critical for compressor engagement. The PCM uses the temperature measurement to turn the A/C compressor off before the evaporator temperatures are cold enough to freeze the condensation on the evaporator core.

When an A/C request is received by the PCM, the A/C compressor clutch only engages through the A/C clutch relay if all of the following conditions are met:

• The PCM does not detect excessively high or low refrigerant pressure from the A/C pressure transducer.
• The PCM does not detect excessively high engine coolant temperature.
• The PCM does not detect an ambient air temperature below 0°C (32°F).
• The PCM has not detected a WOT condition.
• The HVAC control module does not detect an evaporator discharge air temperature below 1°C (33.8°F).

DTC Fault Trigger Conditions 

Possible Sources 

• A/C clutch relay
• Wiring, terminals or connectors
• PCM
• HVAC control module