Air Delivery

WARNING: This page is about a different car, the 2017 Chevrolet Spark. However, it is still accessible from the selected car via links, so may be relevant.

The HVAC control assembly controls the distribution of air by the use of recirculation actuator and the mechanically controlled mode door. The modes that may be selected are:

Defrost - Air flow is directed at the windshield
Defog - Air flow is split between the windshield and floor
Vent - Air flow is directed to the vents located in the instrument panel
Bi - Level - Air flow is split between the instrument panel vents and the floor vents
Floor - Air flow is directed to the floor

The desired mode can be selected with the air distribution control on the HVAC control assembly. Depending on the position of the mode door, air is distributed through various ducts leading to the outlets in the instrument panel. When the defrost position is selected, the HVAC control assembly will command the recirculation actuator to outside air, to aid in reducing window fogging.

Recirculation Operation

The recirculation door controls the amount of exterior air that is directed into the vehicle and is controlled by the recirculation actuator. The recirculation actuator is a two-wire bi-directional electric motor. There are two control circuits that allow actuator operation. The control circuits use either a 0 or 12-volt value to coordinate the actuator movement. When the actuator is at rest, both control circuits have a value of 0 volts. To move the actuator, the HVAC control assembly grounds one of the control circuits while providing the other with 12 volts. The HVAC control assembly reverses the polarity of the control circuits to move the actuator in the opposite direction.