Mode Door Actuator
WARNING: This page is about a different car, the 2008 Mercury Milan, 2008 Lincoln MKZ, and 2008 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
The mode door actuator:
- uses a cam setup to position the 2 airflow mode doors to direct system airflow to the vehicle interior as determined by the HVAC module settings.
- contains a reversible electric motor.
- contains a potentiometer. The potentiometer wiper is connected to the actuator output shaft and moves with the output shaft to indicate the position of the mode door.
A 5-volt signal is applied to one end of the potentiometer and ground to the other. The voltage available at the wiper indicates the position of the potentiometer. The expressed value of the actuator wiper voltage is sent to the HVAC module and is matched with an expected wiper voltage value. The HVAC module then drives the actuator motor in whichever direction is necessary to make the actuator wiper voltage agree with the expected HVAC module wiper voltage value.