Automatic headlamp actuation, function

Automatic driving light actuation function

The following prerequisites are necessary to activate the auto on/off headlamps:

 The rotary light switch (S1) is turned to the "AUTO" position.

 The transmitter key (A8/1) is in position 1 "terminal 15R ON".

The automatic driving light actuation automatically switches the vehicle's driving lights on or off depending on the ambient brightness and weather situation. The light intensity value required for this function is recorded by the rain/light sensor (B38/2). This saves the driver from switching the lights on in inclement weather, darkness or when entering a tunnel.

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The type of driving lights (low beam or high beam) is dependent on the switch position of the headlamp flasher/high beam switch (S144s2) integrated in the combination switch (S144). The driving lights operate as follows:

 If the headlamp flasher/high beam switch of the combination switch is set to the "High beam" position, then driving lights and high beam are the same.

 If the headlamp flasher/high beam switch of the combination switch is set to the "Low beam" position, then driving lights and low beam are the same.

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Response of exterior lights (ABL) when driving off

Function at start of journey (in darkness)

 Transmitter key removed ABL "OFF"

 "Tml. 15C ON" ABL "OFF"

 "Tml. 15R ON" Standing lights "ON"

 "Tml. 15 ON" Standing lights "ON"

 "Tml. 61 ON" Standing lights and driving lights "ON"

Function at end of journey (in darkness)

 "Tml. 61 OFF" Standing lights and driving lights "ON"

 "Tml. 15 OFF" Standing lights and driving lights "ON"

 "Tml. 15R OFF" Standing lights "ON"

 "Tml. 15C OFF" Standing lights "ON"

 Transmitter key removed ABL "OFF"

At the start or end of a journey with daytime running lamps and excellent weather conditions, the ABL are not automatically actuated.

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Networking of components

The components in the high beam function and the headlamp flasher function are networked as follows:

 The rotary light switch is read in directly by the SAM control unit (N10).

 The headlamp flasher/high beam switch of the combination switch is read in directly by the MRM control unit (N80).

 The MRM control unit places the signals on the Controller Area Network bus class C (engine compartment) (CAN-C).

 The EIS [EZS] control unit (N73) reads in these signals and places them on the Controller Area Network bus class B (interior) (CAN-B), where they are read in by the SAM control unit.

 The SAM control unit reads in the signals from the rain/light sensor via CAN-B.

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The following lamps are actuated for the automatic driving light actuation function when required directly by the SAM control unit:

 High beam (E1/6e1) or low beam (E1/6e2) of left XENON lamp unit (E1/6) via xenon control unit (E1/6n1)

 High beam (E2/6e1) or low beam (E2/6e2) of right XENON lamp unit (E2/6) via xenon control unit (E2/6n1)

 Standing light (E1/6e3) of left XENON lamp unit

 Standing light (E2/6e3) of right XENON lamp unit

 Taillight (E3e2) of left taillamp (E3) with model 906.611/613/631/633/635/637/653/655/657/711/713/731/ 733/735 or taillight (E3/6e2) of left taillamp (E3/6) with model 906.111/113/131/133/135/153/155/211/ 213/231/233/235/253/255

 Taillight (E4e2) of right taillamp (E4) with model 906.611/613/631/633/635/637/653/655/657/711/713/731/ 733/735 or taillamp (E4/6e2) of right taillamp (E4/6) with model 906.111/113/131/133/135/153/155/ 211/213/231/233/235/253/255

 Left license plate lamp (E19/1)

 Right license plate lamp (E19/2)

 When the high beam or headlamp flasher is active, the SAM control unit sends a signal to CAN-B. The instrument cluster (A1) receives this signal and actuates the high beam indicator lamp (A1e3).

At the same time, in vehicles with code (E43) Trailer hitch socket, the signals for actuating the above-listed lamps are forwarded over CAN-B to the trailer connection unit [AAG] control unit (N28/1).