Theory Of Operation
WARNING: This page is about a different car, the 2016 Dodge Durango. However, it is still accessible from the selected car via links, so may be relevant.
The window motor contains a hall effect sensor to detect the window position. A hall effect sensor is a transducer that varies its output voltage in response to changes in magnetic field. If the motor loses its counts, it may perform erratically or in very short movements.