Dakota 2WD V8-4.7L (2008)
Air Door Actuator / Motor: Description and Operation
Mode Door Actuator
Description
DESCRIPTION
The two mode door actuators (1) are reversible, 12-volt direct current (DC), servo motors. The mode door actuators are located on the driver side of the
HVAC housing. The mode door actuators are mechanically connected to the floor/defrost and the panel-air doors. The mode door actuators are
interchangeable with the actuators for the blend-air doors and the recirculation-air door. Each actuator is contained within an identical black molded
plastic housing with an integral wire connector receptacle (2). Each actuator also has an identical output shaft with splines (3) that connects it to its
respective door linkage and three integral mounting tabs (4) that allow the actuator to be secured to the HVAC housing. The mode door actuators do not
require mechanical indexing to the mode-air doors, as they are electronically calibrated by the A/C-heater control.
The two mode door actuators can be serviced from underneath the drivers side of the instrument panel.
Operation
OPERATION
Both the floor/defrost actuator and the panel door actuator (mode door actuators) are connected to the A/C-heater control through the vehicle electrical
system by dedicated two-wire leads and connectors of the HVAC wire harness. Each mode door actuator can move the floor/defrost or the panel-air
doors in two directions. When the A/C-heater control pulls the voltage on one side of an actuator motor connection high and the other connection low,
the respective mode-air door will move in one direction. When the A/C-heater control reverses the polarity of the voltage to the motor, the mode-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 respective mode-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 both mode door actuators and the
mode-air doors. The A/C-heater control learns the mode-air 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 mode door actuators are diagnosed using a scan tool.
The mode door actuators cannot be adjusted or repaired and must be replaced if found inoperative or damaged.
