Dimmer

Light Functions

The light check control module controls and monitors
- all external vehicle headlights and lamps both when switched on and switched off (cold and warm monitoring)
- all switches and buttons for light functions
- The functions of the dimmer for the instrument lights and locator lights

Components
With the exception of the brake light switch, all switches scanned by the LCM are designed such that they switch to ground.

The following switches are scanned by the LCM:
- Combined switch for parking light/low beam
- Turn signal/dip switch
- Fog light switch
- brake light switch
- Hazard warning push-button
- Dimmer potentiometer for instrument locator lights

The LCM receives further information via the I-bus/K-bus.

Light switch
When the light switch is in rest position, all contacts are closed (R < 1 Ohm) and the corresponding contact is opened (R> 1 MOhm) in the low beam or high beam position.

The lighting for the light switch is controlled separately by the LCM. It lights at full brightness when the light switch is in the OFF position. It is dimmed to the same extent as the instrument and locator lights when they are switched on.

brake light switch
The brake light switch is permanently monitored by the LCM when terminal R is activated.

It is designed as a Hall sensor and features 3 lines (terminal R, terminal 31, signal line). The test switch is not necessary.

Hazard warning switch
The indicator lamp for the hazard warning function is located in the hazard warning switch. It also serves as a locator light.

Dimmer potentiometer
The dimmed instrument, locator and function lights (terminal 58g) is activated when the light switch is in the parking light or low beam light position.

The voltage generated at terminal 58g is dependent on the position of the dimmer potentiometer.

Activation of indicator lamps in the instrument cluster
The indicator lamps for left turn signal indicator, right turn signal indicator, rear fog light, fog light and high beam located in the instrument cluster are activated via the I-Bus/K-bus.

Lights
The lamps of the vehicle lighting system are monitored both when switched off and switched on (cold and warm monitoring).

The lamps are activated by means of transistors. Due to the fact that they are now short-circuit-protected, the standard lamp fuses are no longer necessary.

The lamps can also be activated via the diagnosis function.

The country-specific functions of the lamp circuits are coded.