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Hazard flashers

Hazard flashers

The hazard flashers are activated with the appropriate switch on the dashboard, whatever the position of the ignition switch. The power to the flasher lamps is supplied via DICE.



Voltage +30 is always fed to pin 22 on the control module via fuse 16. When the switch for the hazard flashers is operated, the breaker closes and pin 3 on the control module is grounded via the switch (25).

The control module then delivers voltage pulses to the indicator lamp in question from:


• pin 69 for LH direction indicators

• pin 47 for RH direction indicators


The indicator lamp (25) in the hazard flasher switch is powered when inactive from pin 49 of the control module and lights dimly.

When the hazard flashers are active the indicator lamp is powered with the same pulses as the LH hazard flashers and flashes at full intensity.

DICE monitors the hazard-flasher circuit internally. The control module does this by measuring current and voltage across a resistor located in the control module on pin 22. If the voltage/current ratio undergoes a change, DICE responds. In the case of high load, the control module shuts off the output. If the load is low, the flash frequency increases.

The flash frequency is normally 90±5 per minute. In the case of low load, i.e. if a low-rated bulb has been fitted or the bulb is defective, the flash frequency will double.

Power to direction-indicator lamps on a trailer, if any, is fed via the connector 258.

Hazard flashers can be activated by TWICE when an alarm is tripped. TWICE outputs the status of the flashers (ON/OFF) onto the bus.

When the hazard flashers are active, the appropriate indicator lamp on the MIU (540) flashes after receiving information on the status of the direction indicators (ON/OFF) from the bus.

Active indicators are also indicated by a "tick-tock" sound, which is generated in the SID unit in response to information from the bus.

If there is no voltage on the control module pin 22, no information is sent to the bus.

The duty cycle of the hazard flashers is normally 50%. It declines if the battery voltage is high or low, at high voltage in order to limit the rise in temperature inside DICE, and at low voltage in order to save the battery. At most, it is reduced to 30%.