Belt Buckle Switch

Belt Buckle Switch
The belt buckle switch is used to detect whether the seatbelt has been fastened or not. The detection arrives as a signal at the relevant satellites. The signal is used for evaluation for the "Seat Belt Reminder SBR" function and for selective triggering of actuators in the event of a crash.
The belt buckle switch is located in the belt tensioner of the drivers and passenger seats. If the side airbag for rear seat passengers option is installed, seat belt tensioners with belt buckle switches are installed on left and right.
The belt buckle switch is a two wire Hall switch. The Hall switch is supplied with voltage by the satellite. The current intake of the switch is the signal for the switch position.
To reduce the general power consumption, the switch is queried in cycles. The belt buckle switch is permanently diagnosed and monitored as of terminal R.
The SBR function is an extension of the seat belt icon that remains ON for a certain period of time (6 see) after terminal 15 ON.
If the driver pulls away without buckling the seat belt, a visual and acoustic warning is issued after the car has covered about 100 meters. The same applies for the front passenger, if the sensors indicate that the front seat is occupied, but the belt has not been buckled.
The belt reminder lights up and the acoustic warning (gong) sounds for 90 see, unless the belt is buckled in the meantime.
The belt buckle is permanently monitored. A warning is issued if status changes while the car is on the move, in other words if the belt buckle is opened.
The seatbelt warning lamp is switched on as of terminal 15 On until the driver inserts the seatbelt in the seatbelt buckle.
If the seatbelt buckle is opened while the vehicle is being driven, the seatbelt warning lamp is activated again.
An acoustic warning is also issued. The acoustic signal is intermittent and is output for up to 90 seconds.