Air Distribution

WARNING: This page is about a different car, the 2011 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.

The HVAC control module controls the mode actuator in order to distribute airflow to a desired outlet. The mode knob provides the vehicle operator with the ability to override the automatic setting. When the mode door is moved to the defrost position, the A/C compressor clutch engages and the recirculation actuator will be moved to the outside air position. In the outside air position, the incoming air is filtered by the passenger compartment air filter.

Dual Zone Operation

The HVAC control module has temperature settings for the driver and the passenger. If the passenger setting is turned OFF then the driver setting controls both driver and passenger and rear seat temperature actuators. The passenger and rear setting cannot be used without the driver setting also being ON. The passenger setting can be turned ON by pressing the PASS button or the passenger colder and warmer buttons, to turn off press the PASS button. The rear control can be turned ON and OFF using the front HVAC control module. The rear control can also be turned ON by touching any rocker button on the control head, the fan blower rocker button when going down in blower speed will turn OFF the control head. When the passenger setting is ON, the passenger temperature can be adjusted independently from the driver setting and the passenger temperature is displayed on the passenger side of the HVAC control module. A different sunload on one side of the vehicle may cause different discharge air temperatures, even when the passenger setting is not turned ON.

Recirculation

The HVAC control module controls the air intake through the recirculation actuator. Recirculation is not available when the mode is in defrost or defog. When the mode is in floor, recirculation will only be available for 3 minutes. If the system is in full (100%) recirculation continuously for more than 20 minutes, the recirculation actuator moves to a 95% recirculation door position. The HVAC control module will prevent the system from returning to the full recirculation position until the next ignition cycle. In the outside air position, the incoming air is filtered by the passenger compartment air filter.