Headlamp Control, Function - GF82.10-P-2009RDM
Model 172.4
as of model year 2017
except code 640 (High-performance LED)
except code 641 (Headlamps, LED, dynamic, left-side traffic)
except 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
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) (except CODE 460 (Canada version) and except CODE 494 (USA version))
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) 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", 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".
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 request "Daytime running lights On" depending on the country coding or if the daytime running lights request was manually activated in the menu "Settings", "Light" via 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 via chassis CAN 1.
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 position light and daytime running light (E1e27) and the right position light and daytime running light (E2e27) directly in vehicles without code 498 (Japan version).
When it is dark, the front SAM control unit deactivates the daytime running lights actuation 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 front SAM control unit terminates the daytime running lights actuation when the vehicle is at a standstill and once a period of t = 3 minutes has expired. If the vehicle is then moved again, the front SAM control unit automatically activates daytime running lights actuation.
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, the front SAM control unit activates the low beams actuation instead of the daytime running lights actuation.
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" 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 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.
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 (except CODE 460 (Canada version) and except CODE 494 (USA version))
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-2059-97TAC | ||
| Overview of exterior lights system components | GF82.10-P-9998RDM |