Service VME - HVAC System Function Changes - C60 C68 C69 control head heat heater fog operation part performance

When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

CONDITION/CONCERN: A/C compressor will run whenever Recirc mode is selected.

As of mid production for model year 2000 (approximately October 1999). The A/C compressor will run whenever Recirc mode is selected. The A/C indicator will not illuminate unless selected on by the driver.

Additionally, Recirc will not be available with HVAC in Floor, Defrost or any combination of Floor and Defrost. The Recirc indicator will flash 3 times to indicate this. HVAC will automatically switch out of Recirc when any Floor/Defrost position is selected.

Operating the A/C compressor in Recirc mode will improve dehumidification and assist in minimizing the chances of fogging. Not allowing Recirc in modes that will direct airflow to the windshield or floor will reduce the amount of moist interior air being distributed on glass surfaces.

All replacement control heads for model year 1999 to present will operate in this way.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.