Defrost Vent/Register Door Actuator
WARNING: This page is about a different car, the 2018 Ford Focus. However, it is still accessible from the selected car via links, so may be relevant.
The defrost vent/register door actuator is a stepper motor style actuator. The HVAC control module monitors the position of the defrost vent/register door by counting the motor steps as it rotates. The HVAC control module drives the actuator motor in the direction necessary to move the defrost vent/register doors to the position set by the vehicle occupants.