Theory Of Operation

WARNING: This page is about a different car, the 2015 Fiat 500. However, it is still accessible from the selected car via links, so may be relevant.

After the initial installation of the A/C Heater Control, the controller is calibrated to each individual door actuator. The recirculation door actuator is connected to the A/C heater control or module by a dedicated two-wire lead and connector of the HVAC wire harness. When the A/C Heater Control 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 A/C Heater Control reverses the polarity of the voltage to the motor, the recirculation door actuator moves in the opposite direction. When the recirculation air door reaches its travel limit, the A/C heater control will turn the voltage off. Unlike the mode and blend door actuators, the recirculation door does not use a position sensor due to the door only has two positions of either open or closed. The A/C Heater Control learns the recirculation door stop positions during the calibration procedure.