DESCRIPTION
This vehicle uses two mode door actuators (1) which are reversible, 12-volt direct current (DC), servo motors. The mode door actuator for the panel/defrost/demist/floor air doors is located on the driver side end of the HVAC air distribution housing. The mode door actuator for the 2nd row air door is located on the rear of the air distribution housing near the front of the floor console area. The mode door actuators are mechanically connected to the mode-air doors.
The mode door actuator is interchangeable with the actuators for the blend-air door(s) 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 door linkage and three integral mounting tabs (4) that allow the actuator to be secured to the HVAC housing. The mode door actuator does not require mechanical indexing to the mode-air doors, as it is electronically calibrated by the A/C-heater control.
OPERATION
The two 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 panel/defrost/demist/floor air doors 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 doors will move in one direction. When the A/C-heater control reverses the polarity of the voltage to the motor, the mode-air doors 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 doors 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 cannot be adjusted or repaired and must be replaced if found inoperative or damaged. See DIAGNOSIS AND TESTING .
Possible causes of an inoperative blower motor include
- Open fuse
- Inoperative blower motor resistor or power module (depending on application)
- Inoperative blower motor switch
- Inoperative mode control switch
- Inoperative blower motor
- Inoperative blower motor circuit wiring or wire harness connectors