Grand Caravan V6-3.3L VIN R (2005)
Rear
Blend Door Actuator
The rear blend door actuator is a reversible, 12-volt Direct Current (DC), servo motor. The single blend door actuator for the rear heating-A/C system is
located on the outboard side of the rear HVAC housing and is mechanically connected to the blend-air door.
The rear blend door actuator is interchangeable with the actuator for the rear mode-air door. Each actuator is contained within an identical black molded
plastic housing with an integral wire connector receptacle. Each actuator also has an identical output shaft with splines that connects it to its respective
door linkage and two integral mounting tabs that allow the actuator to be secured to the rear HVAC housing. The blend door actuator does not require
mechanical indexing to the blend-air door, as it is electronically calibrated by the A/C-heater control.
The A/C-heater control must be recalibrated each time an actuator motor is replaced.
The rear blend door actuator is connected to the front A/C-heater control through the vehicle electrical system by a dedicated two-wire lead and
connector of the rear HVAC wire harness. The rear blend door actuator can move the rear blend-air door in two directions. When the front 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 front 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 front 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 front A/C-heater control uses a feedback signal positioning system to monitor the operation and relative position of the rear blend door actuator and
the blend-air door. The front 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 circuits.
The rear blend door actuator is diagnosed using a DRBIII(R) scan tool.
The rear blend door actuator cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.