Headlamp Control, Function - GF82.10-P-2009RD
Model 172.4 up to model year 2017
except code 615 (Bi-xenon headlamps with active light function)
except code 621 (Intelligent Light System (left-hand traffic))
except code 622 (Intelligent Light System)
Function requirements, general
- No overvoltage or undervoltage (operating voltage range U ≥ 7 ≤ 17.5 V)
Driving lights actuation, general
During driving lights actuation, the standing lights actuation is active; this is described in a separate document.
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
- Function sequence for auto on/off driving lights
- Function sequence for 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 (voltage-coded).
Additional function requirements for low beams actuation
- Terminal 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 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 transmits the request "Low beams indicator lamp On" via the 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: Terminal 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) 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, uses it to generate the request "High beams On", transmits it via interior CAN to the instrument cluster and actuates the left high beams (E1e1) and the right high beams (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".
Model 172.4 up to model year 2016 with code 460 (Canada version)
except code 615 (Bi-xenon headlamps with active light function)
except code 621 (Intelligent Light System (left-hand traffic))
except code 622 (Intelligent Light System)
Model 172.4 up to model year 2016 with code 494 (US version)
except code 615 (Bi-xenon headlamps with active light function)
except code 621 (Intelligent Light System (left-hand traffic))
except code 622 (Intelligent Light System)
The high beams must not be actuated at the same time as the left front fog lamp (E5/1) and the right front fog lamp (E5/2). The last incoming request has priority.
Additional function requirements for daytime running lights actuation
- "Daytime running lights" function activated in "Settings", "Light" menu in instrument cluster
- "Engine running" or "Drive train ready" signal set or vehicle speed v > 3 km/h
- Exterior lights switch in "A" position
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 in vehicles except CODE 498 (Japan version) and except CODE 835 (South Korea vehicles additional parts) actuates the left daytime running lights headlamp (E1/3) and right daytime running lights headlamp (E2/3) directly.
When it is dark, the front SAM control unit switches the daytime running lights headlamp off and activates the low beams actuation.
The ambient brightness is recorded by the light sensor (B38/1) (except CODE 345 (Windshield wiper with rain sensor)) or the rain/light sensor (B38/2) (with CODE 345 (Windshield wiper with rain sensor)). The front SAM control unit reads in the data from the light sensor or the rain/light sensor via the wiper/inside rearview 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.
In vehicles with CODE 460 (Canada version), the daytime running lights headlamps are switched off after t = 3 min when the vehicle is at a standstill. If the vehicle then starts to move again, the front SAM control unit switches the daytime running lights headlamps on.
The daytime running lights have a higher priority compared to the auto on/off driving lights.
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 driving lights are manually switched on via the exterior lights switch (except CODE 460 (Canada version) or except CODE 494 (USA version)).
In vehicles with CODE 498 (Japan version) or CODE 835 (South Korea vehicles additional parts), the front SAM control unit activates the low beams actuation, since no daytime running lights headlamps are installed.
Additional function requirements for auto on/off driving lights
- "Engine running" or "Drive train ready" signal set or vehicle speed v > 3 km/h
- Exterior lights switch in "A" position
- Light sensor or rain/light sensor signals "Darkness recognized"
Function sequence for auto on/off driving lights
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.
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 directly and the data of the light sensor or rain/light sensor via the wiper/inside rearview mirror LIN.
In the auto on/off driving lights, the low beams are automatically switched on or off.
This occurs depending on the ambient brightness or depending on the activities of the windshield wiper system:
- Function sequence for auto on/off driving lights via light sensor or rain/light sensor
- Function sequence for auto on/off driving lights over wiper activities
Function sequence for auto on/off driving lights via light sensor or rain/light sensor
The light sensor or the rain/light sensor evaluates the ambient brightness. The front SAM control unit reads in the data of the light sensor or the rain/light sensor via wiper/inside rearview mirror LIN and activates the low beams actuation if darkness is recognized.
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 system, one refers to wiper, rain or adverse weather light. The front SAM control unit controls this function 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.
Switch-off conditions for auto on/off driving lights:
In the event of light sensor or rain/light sensor failure, the auto on/off driving lights 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 driving lights function remains switched on.
If the wiper startup suppression function is canceled, the auto on/off driving lights remain active for an additional t = 60 s.
| Behavior of exterior lights when auto on/off driving lights activated | ||
|---|---|---|
| Start of trip | Standing lamp | Low beam |
| Circuit 15C OFF | Off | Off |
| Circuit 15C ON | Off | Off |
| Circuit 15R ON | On | Off |
| Terminal 15 ON | On | Off |
| "Engine running" signal or "Drive train ready" signal set or v > 3 km/h |
On | On (high beams permissible) |
| End of trip | Standing lamp | Low beam |
| "Engine running" signal or "Drive train ready" signal set or v > 3 km/h |
On | On (high beams permissible) |
| 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 |
Additional function requirements for headlamp range adjustment
- Driving lights On (low beam/high beam)
Function sequence for headlamp range adjustment (HRA [LWR])
The headlamp range adjustment is installed as passive safety equipment in vehicles fitted with halogen headlamps to prevent them from causing glare to oncoming traffic.
Depending on the load condition of the vehicle, the incline angle of the driving lights can be corrected by turning the headlamp range controller (S1s8).
The left headlamp range adjustment actuator motor (E1m1) and the right headlamp range adjustment actuator motor (E2m1) are actuated voltage-coded in accordance with the position of the headlamp range adjuster.
The power supply is provided via the front SAM control unit, and is switched through to the headlamp range adjustment actuator motors in accordance with the position of the headlamp range controller.
The headlamp range adjustment actuator motors adjust the headlamp units in the front lamp units.
| Electrical function schematic for driving lights actuation | PE82.10-P-2059-97TAA | ||
| Overview of exterior lights system components | GF82.10-P-9998RD |