Actuator, Blend Door: Operation

The blend door actuators are connected to the A/C heater control through the vehicle electrical system by a dedicated two-wire lead and connector. The blend door actuators can move the blend-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 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 A/C heater control makes the voltage to both connections high or both connections low, the blend-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 blend door actuators and the blend-air doors. 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 actuators are diagnosed using a scan tool. Refer to DTC INDEX (1 OF 2) or DTC INDEX (2 OF 2) .

The blend door actuators cannot be adjusted or repaired and must be replaced if inoperative or damaged.