Headlamp: Description and Operation
GF82.10-P-2009G Headlamp Control, Function
MODEL 463.306 /336 /346 up to 31.5.12 as of model year 2011 /YoM 10
MODEL 463.202 /222 /236 /237 up to 31.5.12 as of model year 2009 /YoM 08
MODEL 463.247 /248 /249 /254 up to 31.8.08 as of model year 2007
MODEL 463.270 /271 /303 /340 /341 up to 31.5.12 as of model year 2007
1 Rotary light switch status
2 Automatic light switch daylight sensor status
3 Combination switch status
4 Daytime running lamps activated
5 Vehicle speed signal
6 Steering angle
7 Selector lever position
8 Status of circuit 61
9 Headlamp range adjustment sensor status
10 Actuation of headlamp range adjustment motors
11 Front fog lamps actuation
12 High beam solenoid actuation
13 Xenon headlamp control unit actuation
14 High beam status
A1 Instrument cluster
A1e3 High beam indicator lamp
A51 Headlamp range adjustment rear axle sensor
A52 Front axle sensor (headlamp range adjustment)
B32/1 Automatic light switch daylight sensor
E1l1 Left high beam solenoid
E1m1 Left headlamp range adjustment motor
E1n1 Xenon headlamp control unit
E2l1 Right high beam solenoid
E2m1 Right headlamp range adjustment motor
E2n1 Xenon headlamp control unit
E5/1 Left front fog lamp
E5/2 Right fog lamp
G2 Generator
N3/9 CDI control unit (with diesel engine)
N10/1 Front signal acquisition and actuation module (SAM)
N15/5 Electronic selector lever module control unit
N49 Steering angle sensor
N70 Overhead control panel control unit
N71 Headlamp range adjustment control unit
N73 EZS control unit
N80 Steering column tube module
S1s1 Exterior lamp switch
S4 Combination switch
B Interior CAN
C Drive train CAN
LIN Local Interconnect Network (LIN)
X With diesel engine
Y with gasoline engine
General driving light actuation function sequence
The driving lights actuation consists of several subfunctions:
^ Low beam actuation
^ High-beams actuation
^ Daytime running lamps actuation
^ Automatic driving lights on
^ Automatic headlamp range adjustment (HRA [LWR])
^ Turning lamps
Low beam actuation
Function requirements
^ Circuit 30 ON
^ Rotary light switch in the low beam position or rotary light switch in the Auto position and the automatic light switch daylight sensor detects "Darkness"
Low beam actuation function sequence
The position of the rotary light switch is read in by the front signal acquisition and actuation module.
The front SAM routes the request directly to the xenon headlamp control unit.
The xenon headlamp control unit then actuates the left xenon bulb (E1e8) and the right xenon bulb (E2e8).
When low beam is switched on the light cone is partially hidden by covers.
High-beams actuation
Function requirements
^ Circuit 15R On
^ Low beam ON
High beam actuation function sequence
The high beam actuation is requested by pressing the combination switch forward.
The steering column tube module records the switch position of the combination switch and sends the request to the front SAM via the interior CAN.
The front SAM receives the request and actuates the high beam solenoids, whereby the covers which are partially hiding the light cone of the xenon bulbs are moved away.
Headlamp flasher function sequence
To activate the headlamp flasher, the combination switch must be pulled backwards. The high beam actuation remains active as long as the combination switch is pulled and held.
The function sequence and signal flow of the headlamp flasher actuation are similar to the high beam actuation function.
Feedback
An active headlamp flasher actuation is forwarded by the front SAM to the instrument cluster via the interior CAN.
This then actuates the high beam indicator lamp.
Daytime running lamps actuation
Function requirements
^ Function activated via the instrument cluster (country specific)
^ Circuit 61 ON
Daytime running lights actuation function sequence
The daytime running lights actuation is activated by the front SAM.
The front SAM actuates the xenon bulbs via the xenon headlamp control units.
In countries with statutory daytime running lamp regulations, only the headlamp flasher is permitted in daytime running lamp mode, but not the high beam.
Automatic headlamp actuation
Function requirements
^ Rotary light switch in Auto position
^ Light activation sensor detects "darkness"
Auto on/off headlamps function sequence
Function at start of journey
^ Transmitter key (A8/1) disconnected Exterior lights OFF
^ Circuit 15C ON Exterior lights OFF
^ Circuit 15R ON Standing lights ON
^ Circuit 15 ON Standing lights ON
^ Circuit 61 ON Standing lights/low beam ON (high beam permissible)
Function at end of journey
^ Circuit 61 and circuit 15 ON Standing lights/low beam ON (high beam permissible)
^ Circuit 15R ON Standing lights ON
^ Circuit 15C ON Standing lights ON
^ Transmitter key Exterior lights OFF disconnected
Function while driving
The automatic light switch daylight sensor records the ambient brightness. When darkness is detected, the corresponding request is forwarded by the overhead control panel control unit to the front SAM via the interior CAN.
The front SAM then actuates the xenon bulbs via the xenon headlamp control units.
Function during wiper operation
When the wiper system is actuated for t = 20 s with a wipe cycle period of t < 6 s, the front SAM actuates the xenon bulbs via the xenon headlamp control units.
If there is no wipe cycle for t = 60 s, the driving lights are switched off.
Automatic headlamp range adjustment
Function requirements
^ Circuit 61 ON
^ Driving lights On (low beam/high beam)
Automatic headlight range adjustment function sequence
The automatic headlamp range adjustment serves to correct the headlamp range of the vehicle headlamps as a function of the load or the vehicle pitch motions induced by the vehicle dynamics.
To this end, the headlamp range adjustment control unit reads in the headlamp range adjustment rear axle sensor and the front axle sensor (headlamp range adjustment).
The headlamp range adjustment control unit actuates the left headlamp range adjustment motor and the right headlamp range adjustment motor directly.
Cornering illumination
Function requirements
^ Terminal 61 ON
^ Low beam ON and the automatic light switch daylight sensor detects darkness
^ Turn signaling active and speed v < 40 km/h (not USA) or v < 60 km/h (with USA) or steering angle detected
Cornering lights function sequence
The cornering illumination function enables the traffic lane to be better illuminated in the cornering direction and it is implemented by the left front fog lamp or the right front fog lamp.
In the process, only one front fog lamp is actuated - the fog lamp on the inside of the curve when driving forwards and the fog lamp on the outside of the curve when reversing. It is always switched on and off with dimming.
The front SAM is responsible for evaluating all relevant information and the resulting actuation.
The cornering direction is recognized by the turn signaling function or via the steering angle.
The steering angle, detected by the steering angle sensor, is read in by the steering column tube module and transmitted to the EZS control unit via the drive train CAN. The steering angle is routed by the EZS control unit to the front SAM via the interior CAN.
Pressing the combination switch requests the turn signaling function.
The steering column tube module records the switch position of the combination switch and sends the request to the front SAM via the interior CAN.
The front SAM receives the request and actuates the corresponding front fog lamp.
From a speed of v < 40 km/h, the request via turn signaling has priority over the request by the steering angle.
