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Automatic Interior Lights Control, Function - GF82.20-P-2200RD

Model 172.4 

G13848142Courtesy of MERCEDES-BENZ USA

Shown on model 172.4 as of 01.03.2016 

G13848143Courtesy of MERCEDES-BENZ USA

Shown on model 172.4 up to 29.02.2016 

Function requirements, general 

Automatic interior lights control in general 

The automatic interior lights control implements the actuation of all components of the interior illumination, the exit illumination and the trunk illumination.

The master control unit for the automatic interior lights control is the front SAM control unit.

The automatic interior lights control function encompasses the following subfunctions:

Additional function requirements for locator lighting 

Locator lighting function sequence 

In order to control the locator lighting, the front SAM control unit reads in and evaluates in the following signals:

The front SAM control unit sends the request to switch on the locator lighting via wiper/inside rearview mirror LIN to the overhead control panel control unit.

The following components are actuated:

IMPORTANT Model 172.4

as of model year 2017

with code 877 (ambient lighting)

The footwell lamps are not actuated.

The front SAM control unit in vehicles with code 877 (Ambiance illumination) also sends the "Ambiance illumination On" request to the door control units via interior CAN.

The following components of the ambiance illumination are then actuated:

When the central locking is unlocked, all lamps are switched off after expiration of the time set in the instrument cluster or immediately, if the vehicle is locked again within t = 3 s after unlocking it.

IMPORTANT If the "Ambient illumination" function has been activated via the instrument cluster, it automatically switches itself on when the vehicle is unlocked. This causes the "Standing lights actuation active" signal to be set, which also activates the search and symbol illumination. The search and symbol illumination function is described in a separate document.

Additional function requirements for orientation lighting 

Function sequence for orientation lighting 

For control of the orientation lighting, the front SAM control unit reads in and evaluates the following signals:

The front SAM control unit activates the orientation lighting after circuit 15C is switched off and actuates the following components with a defined brightness value:

The front SAM control unit sends the request to switch on the orientation lighting via wiper/inside rearview mirror LIN to the overhead control panel control unit, which then actuates the following components:

The front SAM control unit in vehicles with code 877 (Ambiance illumination) also sends the "Ambiance illumination On" request to the door control unit via interior CAN.

The following components of the ambiance illumination are then actuated:

With the vehicle doors closed, all lamps are switched off after approx. t = 20 s. The OFF delay time can be switched on or off via the "Settings" menu in the instrument cluster.

The respective selection is sent by the instrument cluster via the interior CAN to the front SAM control unit.

IMPORTANT If the "Ambient illumination" function has been activated via the instrument cluster, it automatically switches itself on when the vehicle is unlocked. This causes the "Standing lights actuation active" signal to be set, which also activates the search and symbol illumination. The search and symbol illumination function is described in a separate document.

Additional function requirements for exit illumination 

Function sequence for exit illumination 

The exit illumination is activated by opening a vehicle door.

To control the exit illumination, the front SAM control unit reads in and evaluates the following signals:

Corresponding to the status of the door lock rotary tumbler switch, the front SAM control unit sends the request to switch on the exit illumination via wiper/inside rearview mirror LIN to the overhead control panel control unit, which then actuates the following components:

The front SAM control unit in vehicles with code U25 (Door sills with "Mercedes-Benz" lettering, illuminated) also actuates the following components:

The illuminated door sill moldings are actuated with different intensities depending on the ambient brightness.

The ambient brightness is recorded by the light sensor (without code 345 (Windshield wiper with rain sensor)) or by the rain/light sensor (with code 345 (Windshield wiper with rain sensor)). The front SAM control unit reads in the signals from the light sensor or the rain/light sensor via the wiper/inside rearview mirror LIN.

If the light sensor or rain/light sensor determines that it is "Night", the illuminated door sill moldings are actuated at 10 % of the possible illumination intensity.

If the light sensor or rain/light sensor determines that it is "Day", the illuminated door sill moldings are actuated at 90 % of the possible illumination intensity.

The front SAM control unit in vehicles with code 876 (Interior lights package) or as of 01.03.2016 with code 877 (Ambiance illumination) also actuates the footwell lamps with the brightness value that corresponds to 100 %.

If all the vehicle doors are closed again and the status of circuit 15 On has been sent by the electronic ignition lock control unit via interior CAN, all lamps are switched off.

The footwell lamps are then actuated in a dimmed state again.

The front SAM control unit in vehicles with code 877 (Ambiance illumination) also sends the "Ambiance illumination On" request to the door control units via interior CAN.

The following components of the ambiance illumination are then actuated:

IMPORTANT To preserve the on-board electrical system battery (G1), with circuit 15 Off, all activated lamps are switched off after a period of up to t = 30 min when a vehicle door is open and after a period of t = 8 s after closing of the last vehicle door.

Function sequence for center console illumination 

In order to control the center console illumination, the front SAM control unit reads in and evaluates the following signals:

The front SAM control unit sends the requests to switch on the illumination via wiper/inside rearview mirror LIN to the overhead control panel control unit, which then actuates the following components:

Additional function requirements for trunk illumination 

Function sequence for trunk illumination 

the rear SAM control unit sends the status of the trunk lid rotary tumbler switch in the trunk lid central locking motor via interior CAN to the front SAM control unit. The front SAM control unit then sends the request to switch on the trunk illumination via interior CAN to the rear SAM control unit, which then actuates the following components of the trunk illumination:

IMPORTANT To preserve the on-board electrical system battery, the right trunk lid warning/ambient lamp and trunk lamp is switched off if the trunk lid is open and circuit 15 is Off after a period of t = 10 min.

After closing the trunk lid, the right trunk lid warning/ambient lamp and trunk lamp is switched off.

Additional function requirements for interior illumination with ATA [EDW] alarm (with CODE 551 (Anti-theft alarm system (ATA [EDW]))) 

Function sequence for interior illumination with ATA [EDW] alarm (with CODE 551 (Anti-theft alarm system (ATA [EDW]))) 

The interior illumination is switched on immediately after an ATA [EDW] alarm has been triggered.

The rear SAM control unit sends the status of the ATA [EDW] via interior CAN to the front SAM control unit.

The front SAM control unit sends the request to switch on the interior illumination via wiper/inside rearview mirror LIN to the overhead control panel control unit, which then actuates the following components of the interior illumination:

The front SAM control unit in vehicles with code 876 (Interior lights package) or as of 01.03.2016 with code 877 (Ambiance illumination) also actuates the footwell lamps with the brightness value that corresponds to 100 % and, in vehicles with code 877 (ambiance illumination), sends the "Ambiance illumination On" request via interior CAN to the door control unit.

The following components of the ambiance illumination are then actuated:

Additional function requirements for interior illumination following an accident with airbag deployment 

Function sequence for interior illumination after accident with airbag deployment 

The interior illumination is actuated in order to provide better orientation for the occupants and the first aiders following an accident.

If the supplemental restraint system control unit detects an accident event, it sends corresponding signals via chassis CAN (up to 29.02.2016) or via chassis CAN 1 (as of 01.03.2016) to the front SAM control unit.

The front SAM control unit receives these signals and evaluates them. The front SAM control unit sends the switch on request via wiper/inside rearview mirror LIN to the overhead control panel control unit, which then actuates the following components of the interior illumination:

The front SAM control unit in vehicles with code 876 (Interior lights package) or as of 01.03.2016 with code 877 (Ambiance illumination) also actuates the footwell lamps with the brightness value that corresponds to 100 % and, in vehicles with code 877 (ambiance illumination), sends the "Ambiance illumination On" request via interior CAN to the door control unit.

The following components of the ambiance illumination are then actuated:

The interior illumination function following an accident with airbag deployment is deactivated under the following conditions:

  Automatic interior lights control electrical function schematic   PE82.20-P-2052-97TAA
  Overview of interior illumination (IBL) system components   GF82.20-P-9997RD 
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