Control Assembly: Description and Operation

The air delivery system directs the flow of air used by the climate control system.

The climate control unit receives battery voltage at all times through fuse 33. With the ignition switch in ON (II), battery voltage is supplied to the control unit through fuse 4. The control unit is grounded at G4O1.

Each of the plenum door motors is driven and controlled by the climate control unit.

The climate control unit applies a reference voltage to each of the four door position switches in the mode control motor. The control unit determines the position of the door by grounding various combinations of position switches. For example, if the BLU, PNK/BLK and GRY wires are grounded, the door and motor move to the HD2 position.

The air mix control motor limit switches and diodes interrupt voltage to the motor when the air-mix door reaches the end of its travel. During start-up, the motor is turned on by the control unit to learn the position sensor readings for its range of travel. The position sensor varies resistance to provide door position feedback through the GRN wire.

The limit switches and diodes for the vent door control motor interrupt voltage to the motor when the vent door reaches the end of its travel. During start-up, the motor is turned on by the control unit to learn the position sensor readings for its range of travel. The position sensor varies resistance to provide door position feedback through the YEL/WHT wire.

The limit switches for the recirculation control motor interrupt voltage to the motor when the door reaches the end of its travel. A position sensor is not required for this door since it only has two positions: full fresh or full recirculation.