GM Service Manual Online
For 1990-2009 cars only

For more information on your vehicle's climate control system, see "Climate Control System" in the owner manual Index.

Air Conditioning Engine Start/Stop Override

With the system in AUTO mode in warm or hot weather, or if the system is in front defrost mode, the engine may continue to run at a complete stop, or it may re-start during a complete stop if the system determines that it is necessary to run the air conditioning compressor to cool the cabin and/or dehumidify the air.

The system may allow the engine to shut off if the cabin temperature selected is met, but engine off time will usually be short.

If you would like to get maximum engine off time in hot weather, select manual operation for vent or bi-level mode; this will prevent the system from keeping the engine running at complete stops; however, this does not provide maximum air conditioning performance.

Selecting a higher air conditioning temperature in hot weather will maximize engine off time.

Manual Operation

Selecting the front defrost mode will disable the engine start/stop operation. You may experience uncomfortably warm cabin temperatures in warm or hot weather if you adjust the climate control system and do not choose front defrost mode. Selecting the defog mode will allow the engine start/stop operation to function.