Air Distribution: Notes
WARNING: This page is about a different car, the 2009 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.