Faulty Left Actuator
Left Actuator harness is open or shorted
Left Actuator circuit poor electrical connection
Faulty Heating, Ventilation, and Air Conditioning (HVAC) Control Module
Engine Light ON (or Service Engine Soon Warning Light)
The Heating, Ventilation, and Air Conditioning (HVAC) Control Module commands the air temperature actuators to move by controlling the voltage supplied on the control circuit. A signal voltage of 0 volts or a signal voltage of 5 volts rotates the air temperature actuator. A voltage of 2.5 volts stops the door. The HVAC control module determines the current position of the actuator by monitoring the voltage on the signal circuit. The feedback potentiometer is a function of the motor position. The HVAC control module controls the air temperature actuator door positions in order to maintain the selected air temperature.