Theory Of Operation

After the initial installation of the HVAC Module, the controller is calibrated to each individual blend/mode door actuator. The actuators are connected to the HVAC Module by a dedicated five-wire sensor and control circuits. The actuator can move the blend/mode-air doors in two directions. When the HVAC Module pulls the voltage on one side of the control circuit high and the other low, the door actuator will move in one direction. When the HVAC Module reverses the polarity of the voltage to the motor, the door actuator moves in the opposite direction. Once the HVAC Module makes the voltage to both control circuits high or low, the door actuator will stop its movement and stay in that position. The blend/mode door actuator contains a three wire potentiometer, which the HVAC Module uses to monitor the relative position of the blend/mode air doors. The HVAC Module learns the blend-air door stop positions during the calibration procedure.