Circuit Description

WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

The HVAC control module commands the air temperature actuator movement with one of three voltage signals applied to the air temperature door control circuit. A low voltage of 0 volts moves the air temperature door toward full hot. A voltage of 2.5 volts stops the actuator. A high voltage of 5 volts moves the air temperature door toward full cold. The HVAC control module determines the current position of the actuator by monitoring the feedback voltage of the air temperature door position signal circuit. The feedback potentiometer position is a function of the actuator position. A high voltage indicates a full cold air temperature door position. A low voltage indicates a full hot air temperature door position. The HVAC control module controls the air temperature door position in order to maintain the selected air temperature.