Auxiliary Air Temperature Actuator

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 Chevrolet Tahoe, 2002 Chevrolet Suburban, and 2002 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

The auxiliary air temperature actuator opens or closes the auxiliary air mixture door to a position to divert sufficient air past the heater core to achieve the desired vehicle temperature. The auxiliary air temperature actuator is a 5 wire actuator that incorporates a electric motor with feed back capability. The auxiliary air temperature actuator has a potentiometer integral to it. A 5-volt reference signal is sent out over the 5-volt reference circuit, through the instrument panel junction block, to the air temperature actuator. A feed back signal is provided by the air temperature door position signal circuit. The control of the auxiliary air temperature actuator is provided by the air temperature door control circuit. As the actuator moves, the voltage on the door position signal circuit changes. The rear auxiliary HVAC control module monitors this signal to calculate the actual door position.

When a request of actuator position change from the rear auxiliary HVAC control module, the auxiliary air temperature door control circuit voltage is varied. A 2.5 volt signal from the rear auxiliary HVAC control module keeps the actuator stationary. A 0 volt or 5 volt signal from the rear auxiliary HVAC control module allows the actuator to rotate to a position determined by the HVAC control module. The feed back potentiometer provides the position of the actuator through a varied 5 volt signal for reference of the rear auxiliary HVAC control module.