Seat Belt Buckle Switch: Description and Operation

The left front seatbelt buckle switch with AB and ETR (S68/3) and right front seatbelt buckle switch with AB and ETR (S68/4) monitor whether the three-point seatbelts on the driver and passenger seats are fastened. If the seatbelt is not buckled they cause the emergency tensioning retractor control module with airbag to actuate the driver and/or passenger airbag when actuation threshold 1 is exceeded.