Seat belt warning: Indication
WARNING: This page is about a different car, the 2001 Saab 9-3. However, it is still accessible from the selected car via links, so may be relevant.
The seat belt warning light (72) is turned on via +15 circuit from fuse 27.
The warning lamp is grounded via pin 28 in TWICE.
The belt warning is also given in the form of an acoustic signal. the signal is given for 6 seconds if a seat belt is not fastened. When the belt is fastened, the acoustic signal stops.
TWICE sends out an acoustic warning (On) to the bus and the SID unit gives an acoustic signal.