Headlamp control, function - GF82.10-P-2009CAM
MODEL 207.3/4 as of model year 2014 without CODE 640 (Headlamps, LED, dynamic, SAE, right-side traffic) without CODE 641 (Headlamps, LED, dynamic, left-side traffic) without CODE 642 (Headlamps, LED, dynamic, right-side traffic)
Function requirements, general
- No overvoltage or undervoltage (operating voltage range U ≥7 ≤17.5 V)
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 function is comprised of the following subfunctions:
- Function sequence for low beam actuation
- Function sequence for high beam actuation
- Function sequence for daytime running lights actuation
- Auto on/off headlamps function sequence
- Function sequence for automatic headlamp range adjustment (HRA [LWR])
The driving lights are actuated corresponding to the position of the exterior lights switch (S1). The front SAM control unit with fuse and relay module (N10/1) reads in the status of the exterior lights switch directly.
Additional function requirements for low beams actuation
- Circuit 15 ON
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 this over the chassis CAN 2 (CAN E2) to the left headlamp control unit (E1n9) and to the right headlamp control unit (E2n9).
The left headlamp control unit actuates the left low beam (E1e2) in the left front lamp unit (E1) and the right headlamp control unit actuates the right low beam (E2e2) in the right front lamp unit (E2).
In addition, the front SAM control unit sends the request "Low beams indicator lamp On" via interior CAN to the instrument cluster (A1), which then actuates the low beams indicator lamp (A1e67).
Additional function requirements for high beam actuation
- For high beams function: Circuit 15 and low beams On
- For headlamp flasher function: Circuit 15R On
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
- Function sequence for headlamp flasher
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) reads in the switch position of the combination switch directly and sends this via chassis CAN 1 (CAN E1) to the front SAM control unit.
The front SAM control unit receives the switch position of the combination switch, uses it to generate the request "High beams On", sends it via interior CAN to the instrument cluster and directly actuates the left high beam (E1e1) and the right high beam (E2e1). The instrument cluster actuates the high beams indicator lamp (A1e3).
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.
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
- "Daytime running lights:" function activated in "Settings", "Light" menu in instrument cluster (except vehicles with code (460) Canada version)
- "Engine running" or "Drive train ready" signal set or vehicle speed v > 3 km/h
- Exterior lights switch in "AUTO" on/off headlamps position
Function sequence for daytime running lights actuation
The instrument cluster sends the "Daytime running lights ON" request depending on the national coding or manually activated in the "Settings", "Lights" menu via interior CAN to the front SAM control unit.
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 the "Drive train operational" signal via chassis CAN 1 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 directly.
The front SAM control unit reads in all the information, evaluates it and sends the "Daytime running lamps ON" request via chassis CAN 2 to the left headlamp control unit and to the right headlamp control unit. The left headlamp control unit actuates the left parking light and daytime running light (E1e13).
The right headlamp control unit actuates the right parking light and daytime running light (E2e13).
In darkness the front SAM control unit also actuates the low beams.
The ambient brightness is recorded by the rain/light sensor (B38/2). The front SAM control unit reads in the data of the rain/light sensor via wiper/inside rear-view mirror LIN (LIN 2).
The daytime running lights actuation is deactivated as soon as the exterior lights switch is turned to the "Standing lights", "Manual driving lights" or "Left parking light" or "Right parking light" position.
On vehicles with code (460) Canada version, the front SAM control unit terminates the daytime running lights actuation when the vehicle is at a standstill once a period of t = 3 minutes has expired. If the vehicle is moved again, the front SAM control unit automatically activates the daytime running lights actuation.
The daytime running lights have a higher priority compared to 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 beam is permissible only when the high beam is manually switched on via the exterior light switch (without code (460) Canada version or without code (494) USA version).
Additional function requirements for auto on/off headlamps
- "Engine running" or "Drive train ready" signal set or vehicle speed v > 3 km/h
- Exterior lights switch in "Auto" position
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 comfort function and does not exempt the driver from following the rules in the road traffic regulations.
The CDI control unit or the ME-SFI [ME] control unit sends the "Engine running" or "Drive train operational" signal via chassis CAN 1 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 directly.
| 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 beam is 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
- Function sequence for auto on/off headlamps via wiper activities
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 cycle time of t ≥ 20 s with a wipe < 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.
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
- "Engine running" or "drive train operational" signal on
- Driving lights On (low beam/high beam)
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 set "Engine running" or "Drive train ready" signal via chassis CAN 1, front SAM control unit and chassis CAN 2 to the left headlamp control unit and the right headlamp 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 headlamp control unit.
On vehicles with code (483) ADVANCED AGILITY package, the adaptive damping system control unit (N51/5) sends all the data required to evaluate the vehicle level over chassis CAN 1, the front SAM control unit and chassis CAN 2 to the left headlamp control unit and to the right headlamp control unit.
To do so, the adaptive damping system control unit evaluates the data from the left rear level sensor, the left front level sensor, the right front level sensor (B22/9) and the right rear level sensor (B22/10).
Zero-point programming is performed at the end of production to compensate for suspension tolerances. With successful programming, visual feedback occurs through the movement of the headlamp units "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 headlamp range adjustment is reduced sharply. The "dynamic mode" is activated depending on the speed change and additional signals from the brake and accelerator pedal positions.
When the vehicle is standing automatic headlamp range adjustment is accomplished in the "dynamic mode".
Information on wheel speed and wheel rotation direction, as indicators of vehicle speed, is sent by the Electronic Stability Program control unit (N30/4) over the chassis CAN 1, front SAM control unit and chassis CAN 2 to the left headlamp control unit and to the right headlamp control unit.
The headlamp control units operate in a in master-slave combination, whereby the left headlamp control unit acts as the master and synchronizes the right headlamp control unit.
The left headlamp control unit actuates the left headlamp range adjustment actuator motor (E1m1).
The right headlamp control unit actuates the right headlamp range adjustment actuator motor (E2m1).
| Electrical function schematic for driving lights actuation | PE82.10-P-2059-97EAC | ||
| Overview of exterior lights system components | GF82.10-P-9998CAM |