Dipped Beam, Xenon: Notes

Fig 1: Identifying Dipped Beam Communication Diagram - Xenon

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Dipped beam is on when the light switch (10) is in position 2 and the ignition is in OFF, ON or START position. When the ignition is ON, the power supply will be applied to the dipped beam lamps by DICE. Dipped beam is used on certain markets as daylight driving lights (light switch in 0 or 1). On some markets there are also side marker lights (234FL/FR). This is an extra filament in the front direction indicators that sends a beam of light to the side through an aperture in the reflector.

To enable DICE to determine what position (0-1--2) the light switch (10) is set to, the control module uses bus information from TWICE and its own pins 39 and 15.

TWICE monitors the parking lights and sends information on the bus (Rear light Left ON/OFF and Rear light Right ON/OFF). The ON message corresponds to switch position 1 and the OFF message corresponds to position 0 or 2.

To enable DICE to determine the position setting, it uses pins 39 and 15. DICE pin 39 is connected to light switch pin 10, which corresponds to position 0. DICE pin 15 is connected to light switch pin 11, which corresponds to position 2.

+X voltage from the ignition switch is fed from pin 11 on the light switch (10) to pin 15 on the control module, whereby the dipped beam relay will be grounded via pin 4 on the control module and the relay will close. +30 voltage is fed through the dipped beam relay via fuse 11 to pin 3 on the left-hand headlamp (663FL) and via fuse 13 to pin 3 on the right-hand headlamp (663FL).