Auxiliary Heater Mode

The auxiliary HVAC control module provides additional airflow and temperature offset for the back seat passengers. The auxiliary blower motor will operate as long as the HVAC control module is ON. Passengers can operate the system in both manual or automatic modes. The only time the auxiliary HVAC control module is not available is when the HVAC control module is in FRONT DEFROST. The auxiliary blower motor icon will flash to indicate that the blower is not available. Auxiliary HVAC temperatures can be set 4°C (7°F) cooler or warmer than the primary setting. The HVAC control module provides power and ground to the auxiliary air temperature actuator. The HVAC control module receives power from the rear fuse block through the ignition 3 voltage circuit. Ground is provided by the ground circuit.

The auxiliary air temperature actuator, located in the air temperature actuator assembly, is a reverse polarity motor. Each circuit provides both power and ground to the auxiliary air temperature actuator. When the auxiliary air temperature actuator is being held in position, both of the auxiliary air temperature door control circuits have 12 volts applied to both sides of the actuator motor. This holds the actuator stationary. When a cooler temperature is requested, one of the auxiliary air temperature door control circuits will ground, driving the auxiliary air temperature actuator to the desired temperature. When a warmer temperature is requested, the other auxiliary air temperature door control circuit will ground. This moves the auxiliary air temperature actuator into the desired offset.