Binding Recirculation Door
Faulty Recirculation Door Actuator
Recirculation Door Actuator harness is open or shorted
Recirculation Door Actuator circuit poor electrical connection
Faulty A/C Heater Module
Engine Light ON (or Service Engine Soon Warning Light)
After the initial installation of the A/C Heater Module, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Module drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar Diagnostic Trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present.