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Main beam

Main beam



The main beam (headlamps) is switched on by operating the dipswitch on the steering column when the light switch is in position 2 and the ignition in position ON (+15 and +54) DICE activates the main-beam relay.

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

TWICE, which operates the parking lights, puts information onto the bus (ON/OFF). The ON message corresponds to switch position 1. The OFF message corresponds to position 1 or 2.

DICE pin 39 is connected to light switch pin 6, which corresponds to position 0. DICE pin 15 is connected to light switch pin 11, which corresponds to position 2.

B+ is supplied to control module pin 15 from connection 11 on the light switch (10). When light switch pin 6 (215) is supplied with voltage, DICE is supplied with +30 on pin 41. DICE lights the main beam by pin 11 on the control module grounding pin 5 on the main/dipped beam relay (8). When the relay is drawn, +30 is fed through the relay via the filament monitor (228b) on to fuse 7 (right main beam lamp) and fuse 9 (left main beam lamp).

The MIU (540) receives power from fuse 10 so that a lamp 47g on the MIU lights up to indicate that the main beam is on.

Filament monitor

The filament monitor is located in the engine bay (relay box). It detects any break in the circuit to the lamps by measuring the current in the circuit. In the event of an open circuit, the filament monitor pin 9 grounds pin 23 of the SID unit. SID displays the message “FRONT LIGHT FAILURE”.

Important

When changing a bulb, use a replacement bulb of the correct wattage, since there could otherwise be damage to components.


Diagnosis

Diagnostic trouble code B2280 is generated in the event of an open circuit or a short circuit to ground in the main-beam relay circuit.

DTCs are not generated if the voltage is below 11 V or during diagnostic communication.

Headlamp flasher



The headlamp flasher can be activated whatever the position of the ignition switch and the light switch by using the dipswitch to the right of the steering wheel.

When the dipswitch (215) is moved to its “spring-loaded” position, the main-beam lamps will be powered with +30 which goes via the filament monitor (228b) and the fuses (7 and 13) to the main-beam lamps (11 FL and 11FR)

The MIU (540) receives power from fuse 10 so that a lamp on the MIU lights up to indicate that the main beam is on.

Diagnosis

This function does not have diagnostics.