Instrument illumination, function - GF82.20-P-2029A

MODEL 203 

With the instrument illumination

• it is necessary to differentiate between function illumination

  and

• push-button unit illumination

The function illumination (display and symbol lights of instrument cluster and the control modules equipped with a display field) is activated when the ignition is switched on (c. 15R)t.

The push-button unit illumination (illumination of control modules, switches and buttons) is activated when the exterior lighting is switched on.

The brightness for the function and push-button unit illumination can be set separately on the instrument cluster.

The instrument cluster equipped with internal light sensor adapts the brightness of the function illumination to the present ambient light within the scope of the preset brightness.

When the exterior lighting is switched on and the push-button unit illumination is activated the instrument cluster also adapts the push-button unit illumination to the ambient light.

Since the brightness of the function illumination must be higher during the day than at night a day and night brightness value are distinguished as well. For this purpose the instrument cluster evaluates the signals "Bright" or "Dark" determined by the overhead control panel control module with the light switch-on sensor and transmitted via the data bus.

The function and push-button unit illumination for the radio, the air conditioning and the stationary heater can be activated without ignition by switching on the corresponding control module. The brightness of the illumination is determined by the brightness value set in the instrument cluster and the function illumination is set to the day or night brightness value according to the ambient light.

After the ignition is switched off the instrument cluster stores the brightness value last present.

Function sequence for actuation of function illumination during the day 

1. The electronic key in the electronic starter switch is switched to position "1" (c. 15R).
2. The instrument cluster (A1) is actuated by the signal "c. 15R ON"  via the data bus and immediately actuates the function illumination using the brightness value stored when the ignition was switched off last.
3. The instrument cluster receives the signal "Bright" from the overhead control panel control module (N70) via the data bus and actuates the function illumination using the high day brightness value.
4. The internal instrument cluster light sensor continuously senses the momentary ambient light and the instrument cluster automatically adapts the brightness of the function illumination to this value within the scope of the brightness value preset individually.

Function sequence for actuation of push-button unit illumination 

1. Basic prerequisites:
   • Ignition is switched on and function illumination activated.
   • It is dark and the instrument cluster (A1) actuates the function illumination with the low night brightness value.
2. Parking lights or the low beams are switched on manually on the light switch module (S1) or by the automatic light actuation feature.
3. The front SAM control module with fuse and relay module (N10/1) transmits the signals "Parking light ON"  or "Low beams ON"  to the instrument cluster via the data bus (CAN-B).
4. The instrument cluster triggers actuation of the push-button unit illumination with the brightness value momentarily present for the function illumination.

   The push-button unit illumination is actuated by and adapted to the momentary ambient light conditions within the scope of the brightness preset individually on the instrument cluster regardless of the day and night brightness values.

Overhead control panel control module, location/purpose/design

GF82.20-P-4110A