Circuit Description

WARNING: This page is about a different car, the 2006 Pontiac Montana SV6, 2006 Chevrolet Uplander, and 2006 Buick Terraza. However, it is still accessible from the selected car via links, so may be relevant.

The HVAC control module controls the HVAC actuators to regulate the airflow and temperature through the HVAC system. The actuators are 2-wire, bi-directional electric motors that share the same common control circuit. When the operator adjusts the actuators, the control module can only operate one actuator at a time due to the shared common control circuit. The control circuits use either a 0 or 12-volt value to coordinate the actuator movement. The HVAC control module reverses the polarity of the control circuits to move the actuator in the opposite direction.

The HVAC control module determines the door position by counting motor pulses on one of the control circuits. The HVAC control module converts the pulses to counts with a range of 0-255 counts.

When a calibration or recalibration procedure is performed, the HVAC control module calculates the door travel range. The HVAC control module compares the total number of pulses to calibrated limits. If the total pulse count is less than or equal to the maximum calibrated limited and more than or equal to the minimum calibrated limit, then the calibration is considered successful.

Air Flow Control 1 refers to the defrost actuator.
Air Flow Control 3 refers to the mode actuator.
Air Flow Control 7 refers to the recirculation actuator.
Air Flow Control 10 refers to the auxiliary mode actuator.
Temperature Control refers to the left air temperature actuator.
Temperature Control 2 refers to the right air temperature actuator.
Temperature Control 3 refers to the auxiliary air temperature actuator.