Heating Operation
WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The purpose of the heater is to supply heat to the interior of the vehicle. The vehicle operator can determine the level of heat by turning the air temperature control switch, located on the HVAC control module, to any setting. The air temperature actuator position is directly effected by the position of the air temperature switch. This position will not change with an A/C request.
When a warm air request is made the HVAC control module will position the air temperature actuator to divert most of the air flow through the heater core. Blower, motor and system mode can be changed regardless of the air temperature setting.