Grand Caravan V6-3.3L VIN R (2005)
Rear Blend Door Actuator
The mode door actuator for the rear heating-A/C system is a reversible, 12-volt Direct Current (DC), servo motor. The mode door actuator is located on
the outboard side of the rear HVAC housing, above the blend door actuator. The mode door actuator is mechanically connected to the mode door.
The rear mode door actuator is interchangeable with the actuator for the rear blend-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 rear mode door actuator does not
require mechanical indexing to the mode-air door, as it is electronically calibrated by the front A/C-heater control.
The A/C-heater control must be recalibrated each time an actuator motor is replaced.
The rear mode door actuator is connected to the front heater-A/C control module through the vehicle electrical system by a dedicated two-wire take out
and connector of the rear HVAC wire harness. The rear mode door actuator can move the mode door in two directions. When the front heater-A/C
control module pulls the voltage on one side of the motor connection high and the other connection low, the rear mode door will move in one direction.
When the module reverses the polarity of the voltage to the motor, the rear mode door moves in the opposite direction. When the module makes the
voltage to both connections high or both connections low, the mode door stops and will not move. These same motor connections also provide a
feedback signal to the front heater-A/C control module. This feedback signal allows the module to monitor the operation and relative positions of the rear
mode door actuator and the mode door. The front heater-A/C control module learns the rear mode door stop positions during the calibration procedure
and will store a Diagnostic Trouble Code (DTC) for any problems it detects in the mode door actuator circuits.The rear mode door actuator can be
diagnosed using a DRBIII(R) scan tool. The rear mode door actuator cannot be adjusted or repaired and, if damaged or faulty, it must be replaced.
