Blend Door Actuator: Description
WARNING: This page is about a different car, the 2003 Dodge Intrepid, 2003 Chrysler Intrepid, 2003 Chrysler Concorde, and 2003 Chrysler 300M. However, it is still accessible from the selected car via links, so may be relevant.
The blend door actuator is an electric motor which mechanically positions the blend door. A potentiometer in the actuator allows the BCM (for both manual and ATC systems) to know the exact position of the blend door at all times. The blend door actuator is not serviceable and must be replaced if found to be defective.