Auxiliary Air Distribution

WARNING: This page is about a different car, the 2007 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.

The auxiliary HVAC control module provides airflow direction and temperature control for the back seat passengers. Passengers can operate the rear HVAC control module in both manual or automatic modes. Auxiliary HVAC mode positions can be set to OFF, VENT, FLOOR and VENT, or FLOOR positions. The front HVAC module provides power and ground to the auxiliary mode actuator. The front HVAC module receives power through the ignition 1 and battery positive voltage circuits from the underhood fuse block. Each circuit provides both power and ground to the auxiliary mode actuator. When the auxiliary mode actuator is being held in position, both of the auxiliary mode door control circuits have 0 volts applied to both sides of the actuator motor. This holds the actuator stationary. When a mode is selected, one of the auxiliary mode door control circuits will ground, driving the auxiliary mode actuator to the desired temperature. Depending on the mode that is requested, the other auxiliary air temperature door control circuit may ground. This moves the auxiliary mode actuator into the desired position.