Seatbelt Buckle Sensor
WARNING: This page is about a different car, the 2020 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
The seatbelt buckles contain integrated sensors that are Hall-effect switches. The seatbelt buckle sensors are serviced with the seatbelt buckle.
On vehicles equipped with rear inflatable seatbelts, the buckle at each rear outboard seating position includes the seatbelt buckle sensor and seatbelt inflator. The rear seatbelt buckle is serviced only as an assembly with the sensor and inflator.