Main lighting, detailed description: Notes

Main and dipped beam, tail lights, number plate lighting and parking lights are part of the main lighting.

Fig 1: Identifying Main Lighting

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Power is supplied to the headlamps from the Underhood Electrical Centre, UEC (342), which has semiconductor outputs. This makes it possible to supply PWM-regulated voltage to the lamps. The output value of the supply voltage is 13.5 V, which extends the service life of the bulb.

IMPORTANT: When changing a bulb, use one with the right output otherwise the components could be damaged.

UEC handles logic for the main lighting. The light switch (10) is connected to BCM (707), which sends out bus messages about the position of the switch.

The dipswitch (215) is connected to the Column Integration Module, CIM (703). CIM sends bus messages about the position of the switch. UEC uses these bus messages to activate main or dipped beam.

The headlamp flasher, a "main beam flash", can be activated regardless of the position of the ignition switch and light switch by using the dipswitch (215) to the right of the steering wheel.

Main beam is operated with the dipswitch (215) and the light switch (10). The dipswitch controls main beam 2 different ways: main beam flash (stalk pulled to spring-back position) and main beam (stalk in a fixed position). Either way, the stalk is pulled towards the steering wheel rim.

For main beam to shine continuously, the light switch (10) must be in position 2.

On certain markets, dipped beam is used as daytime running lights. This depends on how UEC is programmed.