Indicating, hazard warning lights

Turn indicator lights are always switched on by the driver.

Hazard warning lights are also switched on electronically: by the DWA (anti-theft alarm), for example, or by the ISIS (Intelligent Safety Integration System).

• Turn indicator lights have priority over hazard warning lights: as of terminal R ON, indicating is possible, even if the hazard warning system is switched on.
  
• The return movement of the turn indicator is electronically controlled by the light module on receipt of a certain steering-wheel-angle signal.
  

Brief description of components

Turn indicator-low beam switch

The steering-column lever to the left of the steering wheel switches the functions

• Turn indicator (one-touch flashing or continuous flashing left or right) with terminal R On,
  
• Parking light left or right: with terminal R OFF, overpress the switch beyond the engaging point, as for continuous flashing.
  
• High beam and headlight flasher.
  

The steering-column lever no longer engages in the switch positions. The functions are operated by

• Touching the switch to move it forwards or backwards: high beam and low beam
  
• Touching the switch to move it to the right or left: one-touch indicating
  
• Overpressing the engaging point: continuous flashing
  

If the driver operates the steering-column lever

• a message is transmitted to the light module. Signal path: SZL (steering column switch centre) -> data bus BYTEFLIGHT -> SIM (Safety and Information Module) -> data bus BYTEFLIGHT -> ZGM (Central Gateway Module) -> data bus K-CAN SYSTEM -> LM (Light Module).
  
• At the same time, the light module evaluates a direct signal from the steering-column lever. This signal is transmitted across a separate cable, making it independent of the K-CAN SYSTEM data bus.
  

Function limitation in the case of failure of the data buses:

• High beam and headlight flasher only run if the steering-column lever is held.
  
• The indicator light only runs if the steering-column lever is held. no continuous flashing, no automatic reset
  
• No hazard-warning lights in the event of a crash and when arming the anti-theft alarm.
  

Hazard warning lights button

Pressing the hazard warning lights button switches on the hazard warning lights. The hazard warning lights button also flashes.

If the hazard warning lights are switched on electronically by the DWA anti-theft alarm, the hazard warning lights button does not flash.

Light module

The light module controls and monitors the vehicle lights. Information is received and sent via the data bus K-CAN SYSTEM.

In the case of the special equipment xenon headlights, the defects of the xenon headlights are evaluated in the light module.

Emergency operation properties of the light module: The light module is supplied with terminal 30 twice.

If a terminal 30 fails, the following are activated:

• Front lighting: low beam and parking light (each on one side).
  
• Rear lighting: On one side, the outer sidelights/brake lights are activated. On the other side, the inner taillights are activated. The vehicle thus still has lights on both sides. Confusion with a one-track vehicle (motorcycle) is excluded.
  
• Brake light: One side of the brake lights is activated with normal power (ECE coding). This leads to ”one-track” braking, as if for example one brake light had failed.
  

In the case of a failure of the processor, emergency operating mode is activated. Emergency operating mode involves hardware that is completely independent of the light module. Emergency operation properties with failure of the processor:

• Vehicle lighting: At terminal 15 On, the following are switched on: Front low beam and outer rear sidelights / brake lights left and right. The outer sidelights / brake lights left and right are not, as would be normal, dimmed to 10% of their brightness, but operated with full power. This ensures the function of the vehicle lighting irrespective of the position of the light switch.
  
• Brake light: With terminal 15 On, the left and right brake lights are switched on when the brake-light switch is operated (via a hard-wired, direct line from the brake-light switch to the lamp drivers).
  

Function defects with failure of the processor:

• No turn indicators and hazard warning lights, no high beam, no headlight flasher, no fog lights, no rear fog light, no third brake light
  
• No communication across the K-CAN SYSTEM.
  
• No communication with the trailer module
  

SZL (Steering Column Switch Centre)

The steering column switching centre registers the signals of the switches and sensors in the steering wheel and steering column. The SZL also controls all the components located on the steering wheel and the steering column. Information is received and sent via the data bus BYTEFLIGHT.

Front turn indicator lamps

The front turn indicator lamps are filament bulbs. The lamps are monitored by the light module.

Rear turn indicator lamps

The rear turn indicator lamps are filament bulbs. The lamps are monitored by the light module.

Auxiliary turn indicator lights, left and right

The auxiliary turn indicator lights left and right are filament bulbs. The lamps are monitored by the light module.

Indicator lamps and sound transmitter relay for the indicator function

The indicator lamps and sound transmitter relay for the indicator function are in the instrument cluster.

Indicator lamps for the hazard warning flasher function

The indicator lamp for the hazard warning function is in the hazard warning button. The indicator lamp functions as the same time as locating light. The indicator lamp is not switched on when the hazard warning lights are triggered by the DWA alarm.

Main functions

Flashing

For turn indicators, there are two indicator functions:

• One-touch indicating: the turn indicator-low beam switch is operated to the engaging point. The turn indicator lamps are activated a few times. How often the indicator lights are activated depends on the coding. An indicator cycle that is already running is completed. One-touch indicating can be used, for example, when changing lanes.
  
• Continuous flashing: if the turn indicator-low beam switch is pressed beyond the engaging point, the turn indicator lamps are activated with the function ”continuous flashing”. Continuous flashing is terminated automatically at a signal of the steering angle.
  

If one of the turn signal indicator lamps on the vehicles or on the trailer is defective, the flash rate is doubled.

Crash alarm hazard warning lights

If the ISIS (Intelligent Safety Integration System) detects a crash, the hazard warning lights are switched on (dependent on the coding). The hazard warning lights can be switched off again using the hazard warning lights button.

DWA alarm hazard warning lights

The turn indicator lamps are also activated by the DWA anti-theft alarm (dependent on the coding).

• One flash of the turn indicator lamps: DWA is activated
  
• Continuous flashing of all turn indicator lamps: alarm signal
  

Country-specific version

USA

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