See also:

Service Only Mode
This power mode is available for service and diagnostics, and to verify the proper operation of the malfunction indicator lamp as may be required for emission inspection purposes. With the vehicle ...

Service Bulletins
Service Bulletins give additional technical service information needed to knowledgeably service General Motors cars and trucks. Each bulletin contains instructions to assist in the diagnosis ...

Automatic Operation
AUTO (Automatic Fan): When AUTO is selected on the fan control, the system automatically adjusts the fan speed. If the OnStar® system is activated when this position is selected, the fan speed ...