GF82.10-P-2009GVB Headlamp Control, Function

GF82.10-P-2009GVB Headlamp Control, Function
- with CODE (615) Bi-xenon headlamp unit with integrated curve illumination
- with CODE (616) Bi-xenon headlamp unit with integrated asymmetrical curve illumination

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/parking lights actuation is active, which is described in a separate document.

The driving lights actuation function is comprised of the following subfunctions:
^ Low beam actuation function sequence
^ High beam actuation function sequence
^ Daytime running lights actuation function sequence
^ Auto on/off headlamps function sequence
^ Function sequence for automatic headlamp range adjustment (HRA [LWR])

Additional low beams actuation function requirements
^ Circuit 15 On

Low beam actuation function sequence
The low beams actuation is requested by turning the rotary light switch (S1) into the "manual driving lights" position.
The circuit status of circuit 15 is provided on the interior CAN by the EIS [EZS] control unit (N73).
The upper control panel control unit (N72/1) reads in the status of the rotary light switch via the instrument panel LIN and transmits this via the interior CAN to the front SAM control unit (N10).

The front SAM control unit then actuates the xenon headlamp supply module (E1n4) in the left front lamp unit (E1) and the xenon headlamp supply module (E2n4) in the right front lamp unit (E2) directly. The xenon headlamp supply module in the left front lamp unit actuates the xenon headlamp ignition module (E1n2) and thus the left low beams (E1e2). The xenon headlamp supply module in the right front lamp unit actuates the xenon headlamp ignition module (E2n2) and thus the right low beams (E2e2).

Additional function requirements, high beam actuation
^ For high beams function: circuit 15R and low beams On
^ For headlamp flasher function: circuit 15R On

High beam actuation function sequence
The high beams actuation is comprised of the following subfunctions:
^ Function sequence for high beams
^ Headlamp flasher function sequence

Function sequence for high beams
The high beams actuation is requested by pressing the combination switch (S4) forward.
The switch position of the combination switch is read in by the steering column tube module (N80) and made available on the engine compartment CAN. The central gateway control unit (N93) forwards this to the front SAM control unit via the interior CAN.
The circuit status of circuit 15 is made available by the EIS [EZS] control unit on the interior CAN.
The front SAM control unit receives all the relevant information and actuates the left high beam (E1e1) and the right high beam (E2e1) as well as the left high beam solenoid (E1l1) and the right high beam solenoid (E2l1).
The covers that partially cover the light cones of the bi-xenon lights are folded away and thus enable the entire light beam to light up the road surface.
The front SAM control unit then transmits the status "high beams actuation active" via the interior CAN to the instrument cluster (A1). This then actuates the high beam indicator lamp (A1e3).

Headlamp flasher function sequence
The function sequence and the signal flow of the headlamp flasher function are the same as for the high beams function. To request the headlamp flasher, however, the combination switch must be pulled backwards. The high beams actuation remains active for as long as the combination switch is held in this position. When the low beams actuation is not active only the high beams are actuated; the igniting of the xenon bulbs and the ramp-up to full brightness would take too long.

On vehicles with code (460) Canada version or code (494) USA version, the high beams may not be actuated at the same time as the left front fog lamp (E5/1) and right front fog lamp (E5/2). The current incoming request has priority.

Additional function requirements, daytime running lights actuation
^ Function activated via the instrument cluster (only countries without legal daytime running lights specification)
^ Engine running (circuit 61 ON) n > 300 rpm

Daytime running lights actuation function sequence
The request for the daytime running lights function is output depending on the country coding or activated manually by the instrument cluster on the interior CAN.
The circuit status of circuit 61 is made available on the engine compartment CAN by the CDI control unit (N3/9) (for diesel engine) or by the ME-SFI [ME] control unit (N3/10) (for gasoline engine) and forwarded from the central gateway control unit via the interior CAN to the front SAM control unit. The front SAM control unit reads in all of the relevant information, evaluates it, and actuates the xenon headlamp supply modules. The xenon headlamp supply modules then actuate the xenon headlamp ignition modules and thereby the low beams.

The daytime running lights function has a higher priority than the auto on/off headlamps function.
In countries with legal daytime running lights specification only the headlamp flasher is permissible but not the high beams.
The high beams are only permissible when the driving lights are switched on manually (not with code (460) Canada version or code (494) USA version).

Additional function requirements, auto on/off headlamps
^ Engine running (circuit 61 ON) n > 300 rpm
^ Rotary light switch in auto on/off headlamps position
^ Rain/light sensor signals darkness

Auto on/off headlamps function sequence

Journey commencement:
- Transmitter key (A8/1) removed Standing lights/low beams Off
- Circuit 15C ON Standing lights/low beams Off
- Circuit 15R ON Standing lights ON
- Circ. 15 ON Standing lights ON
- Circuit 61 ON Standing lights/low beams ON (high beams permissible)

End of journey:
- Circuit 61 ON Standing lights/low beams ON (high beams permissible)
- Circuit 15R ON Standing lights ON
- Circuit 15C ON Standing lights ON
- Transmitter key disconnected Standing lights/low beams Off

The standing lights are switched off as soon as the driver door is opened with the transmitter key inserted (circuit 15 C).
The circuit status of circuit 61 is made available on the engine compartment CAN by the CDI control unit or by the ME-SFI [ME] control unit and forwarded from the central gateway control unit via the interior CAN to the front SAM control unit.
The ambient brightness is recorded by the rain/light sensor. The status of the rain/light sensor is read in by the overhead control panel control unit (N70) and transmitted via the interior CAN to the front SAM control unit. If darkness is detected, the front SAM control unit actuates the xenon headlamp supply modules. The xenon headlamp supply modules then actuate the xenon headlamp ignition modules and thereby the low beams.

When the windshield wiper system is activated for at least t = 20 s with a wipe cycle time of t < 6 s, the low beams are switched on. When the wipe cycles remain off for at least t = 60 s, the low beams are switched off.

Additional function requirements, automatic HRA [LWR]
^ Engine running (circuit 61 ON) n > 300 rpm
^ 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 following information, which describes the driving state, is incorporated into the computation of the correction values:
- Body-pitch angle from the axis positions
- Vehicle speed for calculating operating mode

On vehicles without code (488) Steel/air suspension or without code (489) AIRmatic (air suspension with level adjustment and adaptive damping system ADS), the headlamp range adjustment control unit (N71) reads in the signals of the right front level sensor (B22/9) and the right rear level sensor (B22/10) and from these calculates the vehicle level.

On vehicles with code (488) Steel/air suspension, the headlamp range adjustment control unit reads in the signals of the right front level sensor.
Information on the rear axle level is made available on the engine compartment CAN by the rear axle level control system control unit (N97).
The headlamp range adjustment control unit reads in all the relevant information and calculates from this the vehicle level.

On vehicles with code (489) AIRmatic (air suspension with level adjustment and adaptive damping system ADS), the information about the vehicle level is made available on the engine compartment CAN by the AIRMATIC control unit with ADS (N51).

The circuit status of circuit 61 is made available on the engine compartment CAN by the CDI control unit or by the ME-SFI [ME] control unit and sent from the instrument cluster to the headlamp range adjustment control unit.

Information on wheel speeds and wheel rotation directions, as an indicator of the vehicle speed, is made available by the ESP control unit (N47-5) on the engine compartment CAN.

This information is required to regulate the adjustment rate of the automatic headlamp range adjustment.
If the vehicle is moving at a constant speed, the automatic headlamp range adjustment system operates in "static mode" at a slow adjustment rate. In the event of acceleration, the "dynamic mode" is activated with a high adjustment rate.

The headlamp range adjustment control unit reads in all the relevant information via the engine compartment CAN, evaluates it and actuates the HRA [LWR] power module (E1n3) at the left front lamp unit and the HRA [LWR] power module (E2n3) at the right front lamp unit. The HRA [LWR] power modules then actuate the left headlamp range adjustment motor (E1m1) and the right headlamp range adjustment motor (E2m1) accordingly.