Rear fog lights switch (161): Connection

The light switch is directly grounded to the body. The rear fog light pin is fed separately via a resistor integrated in BCM. Voltage between the pin and ground will be 0 V when the circuit is closed to ground and approx. 6 V when it is open. If the control module reads 10.2 V, it will interpret it as a break. The LEDs are grounded internally and are supplied PWM from BCM.

Fig 1: Identifying Communication Flow - Rear fog lights switch (161)

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Fig 2: Circuit Diagram - Rear Fog Lights Switch (161)

Courtesy of SAAB-SCANIA OF AMERICA, INC.