Commander 4WD V8-4.7L Flex Fuel (2009)
Air Door Actuator / Motor: Description and Operation
Blend Door Actuator - Operation
Front
OPERATION
The blend door actuators are connected to the A/C-heater control through the vehicle electrical system by a dedicated two-wire lead and connector of the
HVAC wire harness. The blend door actuator(s) can move the blend-air door(s) in two directions. When the A/C-heater control pulls the voltage on one
side of the motor connection high and the other connection low, the blend-air door will move in one direction. When the A/C-heater control reverses the
polarity of the voltage to the motor, the blend-air door moves in the opposite direction.
When the A/C-heater control makes the voltage to both connections high or both connections low, the blend-air door(s) stops and will not move. The
A/C-heater control uses a pulse-count positioning system to monitor the operation and relative position of the blend door actuators and the blend-air
doors. The A/C-heater control learns the blend-air doors stop positions during the calibration procedure and will store a diagnostic trouble code (DTC)
for any problems it detects in the blend door actuator circuits.
The blend door actuator(s) is diagnosed using a scan tool See: Powertrain Management/Computers and Control Systems/Testing and
Inspection/Diagnostic Trouble Code Tests and Associated Procedures.
The blend door actuator(s) cannot be adjusted or repaired and must be replaced if inoperative or damaged.
Rear
OPERATION
The rear blend door actuator is connected to the A/C-heater control through the vehicle electrical system by a dedicated two-wire lead and connector of
the rear heater-A/C wire harness. The rear blend door actuator can move the rear blend-air door in two directions. When the A/C-heater control pulls the
voltage on one side of the motor connection high and the other connection low, the rear blend-air door will move in one direction. When the A/C-heater
control reverses the polarity of the voltage to the motor, the rear blend-air door moves in the opposite direction.
When the A/C-heater control makes the voltage to both connections high or both connections low, the rear blend-air door stops and will not move. The
A/C-heater control uses a pulse-count positioning system to monitor the operation and relative position of the rear blend door actuator and the rear
blend-air door. The A/C-heater control learns the rear blend-air door stop positions during the calibration procedure and will store a diagnostic trouble
code (DTC) for any problems it detects in the rear blend door actuator circuit.
The rear blend door actuator is diagnosed using a scan tool See: Powertrain Management/Computers and Control Systems/Testing and
Inspection/Diagnostic Trouble Code Tests and Associated Procedures.
The rear blend door actuator cannot be adjusted or repaired and must be replaced if inoperative or damaged.
