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Headlamp Control, Function - GF82.10-P-2009FH

Model 238 

Up To Model Year 2021 

except code 631 (Static LED headlamps, left-hand traffic) 

except code 632 (Headlamps, LED, static, right-side traffic) 

except code P35 (Light Package) 

Function requirements, general 

Driving lights actuation, general 

Driving lights actuation includes all functions which serve the optimum illumination of the road while driving.

The driving lights actuation encompasses the following subfunctions:

IMPORTANT The driving lights are actuated corresponding to the position of the exterior lights switch (S1). The front SAM control unit (N10/6) reads in the status of the exterior lights switch directly.

Additional function requirements for low beams actuation 

IMPORTANT The electronic ignition lock control unit (N73) sends the status of circuit 15 to the front SAM control unit over the interior CAN (CAN B).

IMPORTANT Front standing lights actuation is switched off when the low beams are active. This is because of the different light colors of the light source.

Function sequence for low beam actuation 

Turning the exterior lights switch into the "low beams" position requests actuation of the low beams.

The front SAM control unit reads in the status of the exterior lights switch directly, and actuates the left low beam (E1e2) in the left front lamp unit (E1) and the right low beam (E2e2) in the right front lamp unit (E2).

The front SAM control unit also sends the "Low beams indicator lamp ON" request via interior CAN, electronic ignition lock control unit and user interface CAN (CAN HMI) to the instrument cluster (A1), which then actuates the low beams warning indicator.

IMPORTANT The active exterior lights function is displayed via an appropriate information display in the instrument cluster.

If standing lights actuation is active, for example, the instrument cluster actuates the standing lights information display. If low beams actuation is now activated, the instrument cluster switches the standing lights information display off and actuates the low beams information display.

The standing lights actuation is not switched off in the following countries:

Additional function requirements, high beam actuation 

IMPORTANT The electronic ignition lock control unit sends the status of circuit 15 to the front SAM control unit via the interior CAN.

Function sequence for high beam actuation 

The high beams actuation is comprised of the following subfunctions:

Function sequence for high beams 

High beam actuation is requested by pushing the combination switch (S4) forward.

The steering column tube module control unit (N80) directly reads in the switch position of the combination switch and sends it to the front SAM control unit via the chassis FlexRay (Flex E), electronic ignition lock control unit and interior CAN.

The front SAM control unit receives the switch position of the combination switch and actuates the left high beam (E1e1) and the right high beam (E2e1) directly.

In addition, the front SAM control unit transmits the status "High beams ON" via the interior CAN, the electronic ignition lock control unit and the user interface CAN to the instrument cluster, which then actuates the high beams information display..

IMPORTANT Model 238

up to model year 2021

with code 464 (Instrument cluster 12.3" diagonal)

except code 631 (Static LED headlamps, left-hand traffic)

except code 632 (Headlamps, LED, static, right-side traffic)

except code P35 (Light Package)

If high beams actuation is activated, the instrument cluster switches the low beams information display off and actuates the high beams information display.

Function sequence for headlamp flasher 

The function sequence and signal path for the headlamp flasher function correspond to that of the high beam function. However, to request the headlamp flasher function, the combination switch must be pulled backward.

IMPORTANT If the combination switch is pulled back and held, the high beam actuation is active for maximum t = 30 s. The permanently present request is then interpreted as a "stuck combination switch".

Additional function requirements for daytime running lights actuation 

IMPORTANT The electronic ignition lock control unit sends the status of circuit 15 to the front SAM control unit via the interior CAN.

The CDI control unit (N3/9) (diesel engine) or the ME-SFI [ME] control unit (N3/10) (gasoline engine) transmits the "Engine running" or "Drivetrain operational" signal via the drive train CAN (CAN C1), the powertrain control unit (N127), the chassis FlexRay, the electronic ignition lock control unit and the interior CAN to the front SAM control unit.

The electronic stability program control unit (N30/4) sends the "standstill" signal via the chassis FlexRay, electronic ignition lock control unit and interior CAN to the front SAM control unit.

The front SAM control unit reads in the status of the exterior lights switch directly.

Function sequence for daytime running lights actuation 

The front SAM control unit reads in all relevant information, evaluates it and actuates the daytime running light in the left position light and daytime running light (E1e27) and the daytime running light in the right position light and the daytime running light (E2e27) directly in vehicles except code 498 (Japan version).

Depending on the ambient light situation, taillight actuation (without license plate illumination) is activated in twilight a well as daytime running lights actuation. The low beams actuation is activated as it gets darker.

The daytime running lights actuation function is not available in the following countries:

Additional function requirements for auto on/off driving lights 

IMPORTANT The electronic ignition lock control unit sends the status of circuit 15 to the front SAM control unit via the interior CAN.

The "Engine running" or "Drivetrain operational" signal is sent by the CDI control unit or the ME-SFI [ME] control unit to the front SAM control unit via drive train CAN, powertrain control unit, chassis FlexRay, electronic ignition lock control unit and interior CAN. The electronic stability program control unit sends the "standstill" signal via the chassis FlexRay, electronic ignition lock control unit and interior CAN to the front SAM control unit.

The front SAM control unit reads in the status of the exterior lights switch directly.

Function sequence for auto on/off driving lights 

In the auto on/off driving lights, the low beams are automatically switched on or off.

The auto on/off driving lights are purely a comfort function and do not relieve the driver of the need to follow the operating instructions as prescribed by the road traffic regulations.

Behavior of exterior lights when auto on/off driving lights activated at night
Start of trip  Standing lamp  Low beam 
Transmitter key (A8/1) not in the vehicle interior Off Off
Transmitter key in the vehicle interior Off Off
Circuit 15R ON On Off
Terminal 15 ON On after t = 2 s Off
"Engine running" or "drivetrain operational" signal set or "standstill" signal not set On On (high beams permissible)
End of trip 
At the end of a trip, overlaps may occur between the auto on/off driving lights and the headlamp switch-off delay.		 Standing lamp  Low beam 
"Engine running" or "drivetrain operational" signal set or "standstill" signal not set On On (high beams permissible)
Circuit 15R ON On after t = 2 s Off
Transmitter key in the vehicle interior (driver door closed) On Off
Transmitter key in the vehicle interior (driver door open) Off Off
Transmitter key not in the vehicle interior Off Off

The low beams are switched on or off depending on the ambient brightness or depending on the activities of the windshield wiper system:

Function sequence for auto on/off driving lights over light sensor in rain/light sensor with additional functions 

The light sensor records the ambient brightness. The rain/light sensor with additional functions reads in the signals of the light sensor directly, evaluates them and transmits the "Low beams ON" request via the rain/light sensor LIN (LIN B16) to the front SAM control unit. The front SAM control unit then activates the low beams actuation.

IMPORTANT If the light sensor fails, the front SAM control unit activates the low beams actuation until the engine stops.

When the vehicle is being driven through a tunnel and if the wiper start suppression function is active, the auto on/off driving lights function remains switched on.

Function sequence for auto on/off driving lights over wiper activities 

If the low beams are switched on or off due to the activities of the windshield wiper, this is referred to as "Adverse weather light". The front SAM control unit actuates the windshield wiper system.

If the windshield wiper system is activated for t ≥ 20 s with a wipe cycle time of t < 6 s, the front SAM control unit activates low beam actuation. If there are no wipe cycles for t ≥ 60 s, low beams actuation is deactivated.

IMPORTANT If the wiper startup suppression function is canceled, the auto on/off driving lights remain active for an additional t = 60 s.

Additional function requirements for headlamp range adjustment (HRA [LWR] (except code 489 (AIR BODY CONTROL)) 

Function sequence for HRA (except code 489 (AIR BODY CONTROL)) 

The HRA [LWR] is installed as an item of passive safety equipment to prevent oncoming traffic from being dazzled.

The incline angle of the driving lights can be corrected by operating the headlamp range controller (S1s8).

The headlamp range controller actuates the left headlamp range adjustment actuator motor (E1m1) and the right headlamp range adjustment actuator motor (E2m1) directly.

The left headlamp range adjustment actuator motor moves the headlamp unit in the left front lamp unit.

The right headlamp range adjustment actuator motor moves the headlamp unit in the right front lamp unit.

  Electrical function schematic for driving lights actuation   PE82.10-P-2059-97DCA
  Overview of exterior lights system components   GF82.10-P-9998FH 
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