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Headlamp control, function - GF82.10-P-2009CAA

MODEL 207.3/4 up to model year 2014 with CODE 615 (Bi-xenon headlamp unit with integrated curve illumination) 

MODEL 207.3/4 up to model year 2014 with CODE 616 (Bi-xenon headlamp unit with integrated asymmetric curve illumination) 

MODEL 207.3/4 up to model year 2014 with CODE 621 (Intelligent Light System (left-hand traffic)) 

MODEL 207.3/4 up to model year 2014 with CODE 622 (Intelligent Light System (right-hand traffic)) 

Function requirements, general 

Driving lights actuation, general 

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

During driving lights actuation, the standing lights actuation is active; this is described in the "Standing/parking lights actuation, function" information.

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 status of the exterior lights switch is read in directly by the front SAM control unit with fuse and relay module (N10/1) in model 207.3 up to 31.5.10 over instrument panel LIN (LIN 1) and in model 207.3 as of 1.6.10, model 207.4 (voltage-coded).

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).

Function sequence for low beam actuation 

Turning the exterior lights switch to the "Manual driving lights" position requests actuation of the low beams.

The front SAM control unit reads in the status of the exterior lights switch and sends the request through a voltage signal straight to the left xenon light control unit (E1n1) on the left front lamp unit (E1) and to the right xenon light control unit (E2n1) on the right front lamp unit (E2). It additionally transmits the request "Low beams indicator lamp On" via interior CAN to the instrument cluster (A1), which then actuates the low beams indicator lamp (A1e67).

The left xenon light control unit actuates the left xenon bulb with integrated ignition module (E1e10). The right xenon light control unit actuates the right xenon bulb with integrated ignition module (E2e10).

Additional function requirements for high beam actuation 

IMPORTANT The electronic ignition lock control unit sends the status of circuit 15 to the front SAM control unit over 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 position of the combination switch and transmits it to the front SAM control unit via the chassis CAN (CAN E).

The front SAM control unit receives the switch position of the combination switch and uses this to generate the request "High beams On". The front SAM control unit then sends the switch position of the combination switch over the front end CAN (CAN G) to the xenon light control unit and the "high beams indicator lamp ON" request over the interior CAN to the instrument cluster. The instrument cluster then actuates the high beam indicator lamp (A1e3). The left xenon light control unit actuates the left light distribution actuator motor (E1m3) over the left headlamp LIN (LIN G1). The right xenon light control unit actuates the right light distribution actuator motor (E2m3) over the right headlamp LIN (LIN G2). The rollers which partially cover up the xenon bulb's light cone, are turned away thereby uncovering the entire light beam to illuminate the traffic lane.

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". Since no separate high beams are installed to implement the headlamp flasher function, the xenon bulbs must be illuminated when low beams actuation is not active.

IMPORTANT On vehicles with code (460) Canada version or code (494) USA version, the high beams function must not be used if left front fog lamp (E5/1) and right front fog lamp (E5/2) actuation is active.

The currently present request has priority.

Additional function requirements for daytime running lights actuation 

Function sequence for daytime running lights actuation 

The instrument cluster sends the "daytime running lamps ON" request depending on the country coding or manually activated in the "Settings", "Light" menu over the interior CAN.

The CDI control unit (N3/9) (with diesel engine) or the ME-SFI [ME] control unit (N3/10) (with gasoline engine) sends the "engine running" or "drivetrain operational" signal over the chassis CAN.

The instrument cluster sends the vehicle speed over the interior CAN.

The front SAM control unit reads in all relevant information, evaluates it and actuates the left daytime running light (E1/3) and right daytime running light (E2/3) on vehicles without code (498) Japan version.

On vehicles with code (498) Japan version, the daytime running light function is output by the low beam actuation, because daytime running lights are not installed.

When dark, the front SAM control unit actuates the daytime running light headlamps with reduced power and also activates the low beam actuation.

The ambient brightness is recorded by the rain/light sensor (B38/2). The front SAM control unit reads in the status of the rain/light sensor via wiper/inside rearview mirror LIN (LIN 2).

IMPORTANT The daytime running lights actuation is deactivated as soon as the exterior lights switch is turned to position "Standing lights", "Manual driving lights" or "Left parking light" or "Right parking light" (model 207.3 as of 1.6.10, model 207.4).

IMPORTANT On vehicles with code (460) Canada version, the daytime running light actuation is switched off after expiration of a time interval of t = 3 min when the vehicle is standing still. When the vehicle then starts to move again, the front SAM control unit automatically activates daytime running lights actuation.

IMPORTANT The daytime running lights have a higher priority than the auto on/off headlamps.

In countries with legal daytime running light requirements, only the headlamp flasher is permissible but not the high beams. The high beams are permissible only when the high beams are manually switched on over the exterior lights switch (without code (460) Canada version and without code (494) USA version).

Additional function requirements for auto on/off headlamps 

Auto on/off headlamps function sequence 

With the auto on/off headlamps, the low beams are automatically switched on or off.

The auto on/off headlamps function is no more than a convenience system and does not exempt the driver from following the rules of the road traffic regulations.

The CDI control unit or the ME-SFI [ME] control unit sends the "engine running" signal or the "drive train operational" signal over the chassis CAN to the front SAM control unit.

The instrument cluster sends the vehicle speed to the front SAM control unit over the interior CAN.

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

Behavior of exterior lights with active auto on/off headlamps:     
Start of trip  Standing lamp  Low beam 
Circuit 15C OFF Off Off
Circuit 15C ON Off Off
Circuit 15R ON On Off
Circuit 15 ON On Off
"Engine running" or "drive train operational" signal set or vehicle speed v > 3 km/h On On (high beams permissible)
End of trip  Standing lamp  Low beam 
"Engine running" or "drive train operational" signal set or vehicle speed v > 3 km/h On On (high beams permissible)
Circuit 15 ON On Off
Circuit 15R ON On Off
Circuit 15C ON (driver door closed) On Off
Circuit 15C ON (driver door open) Off Off
Circuit 15C OFF Off Off

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

Function sequence for auto on/off headlamps over rain/light sensor 

Ambient brightness is assessed by the rain/light sensor. The front SAM control unit reads in the data of the rain/light sensor via wiper/inside rear-view mirror LIN and activates the low beams actuation if darkness is recognized.

Function sequence for auto on/off headlamps via wiper activities 

If the low beams are switched on or off due to the activities of the wiper system, one refers to wiper, rain or adverse weather light. The front SAM control unit controls the wiper system and evaluates the data of the rain/light sensor or the wipe request via the combination switch for this.

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 In the event of rain/light sensor failure, the auto on/off headlamps are not deactivated until the engine is switched off. When the vehicle is being driven through a tunnel and if the wiper start suppression function is active, the auto on/off headlamps function remains switched on.

If the wiper start suppression function is canceled, the auto on/off headlamps remain active for an additional t = 60 s.

Additional function requirements for automatic headlamp range adjustment 

Function sequence for automatic HRA [LWR] 

The automatic HRA [LWR] permits the correction of the headlamp range of the vehicle headlamps as a function of the load or the vehicle pitch motions induced by the vehicle dynamics.

The CDI control unit or the ME-SFI [ME] control unit sends the "Engine running" or "Drivetrain operational" signal set over the chassis CAN, front SAM control unit and the front end CAN to the left xenon light control unit and to the right xenon light control unit.

In order to determine the current vehicle level in vehicles without code (483) ADVANCED AGILITY package, the voltage signals of the left rear level sensor (B22/7) and left front level sensor (B22/8) are read in directly by the left xenon light control unit.

On vehicles with code (483) ADVANCED AGILITY package the adaptive damping system control unit (N51/5) reads in the voltage signals of the following sensors and sends them over the chassis CAN, front SAM control unit and front end CAN to the left xenon light control unit:

IMPORTANT Zero-point programming is performed at the end of production to compensate for suspension tolerances.

Successful programming is confirmed by visual feedback by the motion sequence of the headlamps "center-down-up-center".

If the vehicle is moving at a constant speed, the automatic headlamp range adjustment system operates in "static mode" at a slow adjustment rate.

When the vehicle is accelerated, the "dynamic mode" is activated and the reaction time of the system is reduced sharply. The "dynamic mode" is activated depending on the amount of speed change and additional signals such as the brake pedal and the accelerator pedal positions.

IMPORTANT When the vehicle is standing automatic headlamp range adjustment is accomplished in the "dynamic mode".

Information on wheel speeds, as indicators of vehicle speed is sent by the Electronic Stability Program control unit (N30/4) (without code (233) DISTRONIC PLUS) or the Premium Electronic Stability Program control unit (N30/7) (with code (233) DISTRONIC PLUS) over the chassis CAN, front SAM control unit and the front end CAN to the xenon light control units.

Both xenon light control units receive this information and communicate with each other via front end CAN.

The xenon light control units operate in a master/slave combination, whereby the left xenon light control unit acts as the master and synchronizes the right xenon light control unit.

The left xenon light control unit actuates the left headlamp range adjustment actuator motor (E1m1) over the left headlamp LIN.

The right xenon light control unit actuates the right headlamp range adjustment actuator motor (E2m1) over the right headlamp LIN.

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