Power Seat Position Sensors
WARNING: This page is about a different car, the 2006 Honda Odyssey and 2005 Honda Odyssey. However, it is still accessible from the selected car via links, so may be relevant.
Each motor has a sensor that detects motor rotation and sends a pulse to the power seat control unit when the motor rotates. The control unit stores the number of pulses in its memory, and the seat position is memorized.