GF82.10-P-2009RI Headlamp Control, Function
GF82.10-P-2009RI Headlamp Control, Function
driving lights actuation, general
The driving lights actuation includes all functions which serve the optimum illumination of the road while driving.
The standing/parking lights actuation is active during driving lights actuation.
The standing/parking lights actuation is described in a separate document.
The driving lights actuation comprises 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 function requirements, low beam actuation
^ Circuit 15 On
^ Rotary light switch (S1) in manual driving lights position
Low beam actuation function sequence
The circuit status of circuit 15 is provided on the interior CAN by the EIS [EZS] control unit (N73). The driver-side SAM control unit (N10/10) reads in the status of the rotary light switch directly, transmits the request for low beam actuation via interior CAN to the front passenger-side SAM control unit (N10/11) and actuates the xenon headlamp control unit (E1n1) at the left front lamp unit (E1). The front passenger-side SAM control unit receives the request and actuates the xenon headlamp control unit (E2n1) at the right front lamp unit (E2). The xenon headlamp control units then actuate the left bixenon light with integrated ignition module (E1e10) and the right bixenon light with integrated ignition module (E2e10).
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 beam actuation is requested by pressing the combination switch (S4) forward. The steering column tube module (N80) reads in the switch position of the combination switch directly and sends the request for high beam actuation via interior CAN. The central gateway control unit (N93) relays it via the diagnostic CAN to the xenon headlamp control unit at the left front lamp unit, which as master synchronizes the xenon headlamp control unit at the right front lamp unit.
The xenon headlamp control units then actuate the left high beam solenoid (E1l1) and the right high beam solenoid (E2l1), which cause the covers that are partially covering the bixenon lamp light cones to be swiveled away.
In addition, the driver-side SAM control unit and the front passenger-side SAM control unit receive the request for high beam actuation. The driver-side SAM control unit actuates the left high beam (E1e1) and the front passenger-side SAM control unit actuates the right high beam (E2e1). The status message "high beam actuation active" is transmitted by the driver-side SAM control unit via the interior CAN to the instrument cluster (A1). The instrument cluster 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 identical to that of the high beams function. To request the headlamp flasher function, the combination switch must be pulled backward.
The high beams actuation remains active for as long as the combination switch is held in this position.
If low beam actuation is not active, only the left high beam and the right high beam are switched on; it would take too long to ignite the bixenon lights.
The high beams function must not be executed during active front fog light actuation for vehicles with code (494) USA version. 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 (TFL) function is issued based on the country coding or through manual activation from the instrument cluster on the interior CAN.
The status of circuit 61 is made available by the ME-SFI [ME] control unit (N3/10) on the engine compartment CAN. The instrument cluster receives it and transmits the request to switch on the TFL via the interior CAN to the driver-side SAM control unit. The driver-side SAM control unit receives the request to switch on the TFL and transmits it as a request for low beam actuation to the front passenger-side SAM control unit. The SAM control units then actuate the corresponding xenon headlamp control unit, which then ignites the bixenon lights.
The daytime running lights have a higher priority compared to the auto on/off headlamps.
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 (without code (494) USA version).
Additional function requirements, auto on/off headlamps
- Engine running (circuit 61 ON) n > 300 rpm
- Rain/light sensor (B38/2) reports darkness
- Rotary light switch in auto on/off headlamps position
Auto on/off headlamps function sequence
Journey commencement:
- Transmitter key (A8/1) removed Exterior lights (ABL) Off
- Circuit 15C ON Exterior lights OFF
- Circuit 15R ON standing lights ON
- Circ. 15 ON standing lights ON
- Terminal 61 ON standing lights/low beams ON (high beams permissible)
End of journey:
- Terminal 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 Exterior lights OFF
If the driver door is opened with circuit 15C On, the standing lights are switched off.
The status of the rain/light sensor is read in by the overhead control panel control unit (N70) and made available on the interior CAN. The driver-side SAM control unit receives the information darkness detected" from the rain/light sensor and transmits the request for low beam actuation via interior CAN to the front passenger-side SAM control unit.
The SAM control units then actuate the corresponding xenon headlamp control unit directly, which then ignites the bixenon lights.
When the windshield wiper system is activated for t ≥20 s with a wipe cycle time t < 6 s, the low beams are switched on. If the wipe cycles remain off for t ≥60 s, the low beams are switched off.
Additional function requirements, automatic HRA [LWR]
^ 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.
On vehicles without code (487) Active Body Control (ABC), the left rear level sensor (B22/7) and the left front level sensor (B22/8) are read in directly by the xenon headlamp control unit at the left front lamp unit.
On vehicles with code (487) Active Body Control (ABC), the data of the left front level sensor, right front level sensor (B22/9), left rear level sensor and right rear level sensor (B22/10) are read in by the ABC control unit (N51/2), evaluated and made available on the engine compartment CAN.
Information on vehicle speed is made available by the ESP, SPS [PML] and BAS control unit (N47-5) on the engine compartment CAN.
All relevant information is made available by the central gateway control unit to the xenon headlamp control unit at the left front lamp unit via the diagnostic CAN.
The xenon headlamp control unit at the left front lamp unit processes this data and transmits corresponding correction data to the xenon headlamp control unit at the right front lamp unit via the diagnostic CAN.
The xenon headlamp control units operate in a master-slave combination and communicate with each other over the diagnostic CAN. The xenon headlamp control unit at the left front lamp unit actuates the left headlamp range adjustment motor (E1m1) and the xenon headlamp control unit at the right front lamp unit actuates the right headlamp range adjustment motor (E2m1).
