Seat Belt Switches
WARNING: This page is about a different car, the 2002 Toyota Camry. However, it is still accessible from the selected car via links, so may be relevant.
Seat belt switches are a component of the left and right front seat belt buckles. Right front seat belt buckle includes seat occupation sensor. Seat belt switches send inputs to air bag sensor assembly, indicating whether front seat belts are buckled or not, and if right front seat is occupied.