Description of operation: Notes
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 belt warning light is turned on when the ignition is ON (+15 and +54 circuits) and when the driver's or front-seat passenger's seat belt is not fastened.
The belt contact (70D/70P) is closed when the seat belt is not fastened, and open when it is.
The front passenger seat cushion contains a sensor which detects load. The passenger seat sensor (614P) is connected across pins 5 and 21 of TWICE. Voltage is supplied to the sensor from pin 5 via a resistor in TWICE, and pin 21 is grounded.
The resistance of the sensor varies depending on the load exerted on it. TWICE detects the voltage across the sensor. When the resistance is below 50 kOhm, the load on the seat is considered to mean that it is occupied.