RAM 3500 HD Truck 4WD L6-6.7L DSL Turbo VIN A (2007)
Air Door Actuator / Motor: Description and Operation
Mode Door Actuator
Description
DESCRIPTION
The mode door actuators are reversible, 12-volt direct current (DC) servo motors. The heating-A/C systems on this vehicle use two mode door actuators.
One for the panel/floor-air door and one for the defrost-air door.
Both the defrost door actuator (1) and the panel/floor door actuator (2) and the are located on the driver side end of the HVAC housing (3), close to the
dash panel.
All actuators (1) are interchangeable with each other. 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.
Operation
OPERATION
The 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. The mode door actuators can move the defrost-air door and the panel/floor-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 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 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 the 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)
