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 air temperature actuator opens the air mixture door to a position to divert sufficient air past the heater core to achieve the desired vehicle temperature. The air temperature actuator is a 5 wire actuator that incorporates a electric motor with feed back capability. Power is provided by ignition 3 voltage circuit through the left I/P fuse block. Ground is provided by the ground circuit through the HVAC control assembly. The air temperature actuator has a potentiometer integral to it. A 5-volt reference signal is sent out over the 5-volt reference circuit to the air temperature actuator. A feed back signal is provided by the air temperature door position signal circuit. As the actuator moves the voltage on the door position signal circuit changes. The HVAC control assembly monitors this signal to calculate the actual door position.

The control of the air temperature actuator is provided by the air temperature door control circuit. When a request of actuator position change from the HVAC control assembly, the air temperature door control circuit voltage is varied. A 2.5 volt signal from the HVAC control assembly keeps the actuator stationary. A zero volt or 5 volt signal from the HVAC control assembly allows the actuator to rotate to a position determined by the HVAC control assembly.