Blend Door Actuator: Operation

WARNING: This page is about a different car, the 2004 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.

The blend door actuator is connected to the A/Cheater control through the vehicle electrical system by a dedicated two-wire take out and connector of the HVAC wire harness. The blend door actuator can move the blend-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 blend-air door will move in one direction. When the A/C-heater control reverses the polarity of the voltage to the motor, the blend-air door moves in the opposite direction. When the module makes the voltage to both connections high or both connections low, the blend-air door stops and will not move. These same motor connections also provide a feedback signal to the A/C-heater control. This feedback signal allows the A/C-heater control to monitor the operation and relative positions of the blend door actuator and the blend-air door. The A/C-heater control learns the blend-air door stop positions during the calibration procedure and will store a diagnostic trouble code (DTC) for any problems it detects in the blend door actuator circuits.

The blend door actuator can be diagnosed using a DRBIII(R) scan tool. Refer to ELECTRONIC CONTROL MODULES for more information. The blend door actuator cannot be adjusted or repaired and, if damaged or faulty, it must be replaced.