Automatic headlamp actuation, function

P82.10-3997-09

Shown with code (550) Trailer hitch

B38/2 Rain/light sensor

E1e2 Left low beam

E1e3 Left standing and parking lamp

E1l1 Left high beam solenoid

E1n1 Xenon headlamp control unit

E2e2 Right low beam

E2e3 Right standing and parking lamp

E2l1 Right high beam solenoid

N80 Steering column module

N93 Central gateway control unit

S1 Exterior lamp switch

S4 Combination switch

S15/1e1 Left license plate lamp

S15/1e2 Right license plate lamp

X58 Trailer hitch socket (13-pin)

E2n1 Xenon headlamp control unit

E3e2 Left taillamp and parking lamp

E4e2 Right taillamp and parking lamp

G2 Alternator

N10 SAM control unit

N28/3 Trailer control unit

N70 Overhead control panel control unit

Function requirements

Function requirements for automatic driving lights:

 The rain/light sensor (B38/2) has recognized "darkness".

 The rotary light switch (S1) is in position "AUTO".

Illumination activation is dependent on the light conditions outside the vehicle, which are recorded by the rain/light sensor (B38/2).

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Networking and information flow

Information flow from combination switch (S4) to SAM control unit (N10):

 The combination switch (S4) is read in discretely by the steering column module (N80).

 The steering column module (N80) sends the signals to the Controller Area Network bus Class B (interior) (CAN-B).

 The SAM control unit (N10) reads in the signals from CAN-B.

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Information flow from rain/light sensor (B38/2) to SAM control unit (N10):

 The rain/light sensor (B38/2) measures the light conditions outside the vehicle, converts them into electrical signals and then forwards these signals discretely to the overhead control panel control unit (N70).

 The overhead control panel control unit (N70) stores the signals on the CAN-B bus.

 The SAM control unit (N10) reads in the signals from CAN-B and actuates, when "darkness" has been recognized, the exterior lights to match the circuit status.

The rotary light switch (S1) is read in discretely by the SAM control unit (N10).

The SAM control unit (N10) actuates the following control units via discrete lines:

 Xenon headlamp control unit (E1n1)

 Xenon headlamp control unit (E2n1)

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The Xenon headlamp control unit (E1n1) discretely actuates the following components:

 Xenon headlamp ignition module (E1n2)

 Left low beam (E1e2)

 Left high beam solenoid (E1l1) and thus the left high beam (E1e1)

The Xenon headlamp control unit (E2n1) discretely actuates the following components:

 Xenon headlamp ignition module (E2n2)

 Right low beam (E2e2)

 Right high beam solenoid (E2l1) and thus the right high beam (E2e1)

 The vehicle's variant coding is stored in the central gateway control unit (N93) and forwarded over the Controller Area Network (data bus/CAN bus) (CAN) to the control units installed in the vehicle.

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Combination of circuit status and exterior lights

The following combination between the circuit status and exterior lights is valid when driving off:

 Circuit 15C OFF Exterior lights not activated

 Circuit 15C ON Exterior lights not activated

 Circuit 15R ON Standing lamp activated

 Circ. 15 ON Standing lamp activated

 Terminal 61 ON Standing lamp and low beam activated (high beam possible)

The following combination between the circuit status and exterior lights is valid when finishing a journey:

 Terminal 61 ON Standing lamp and low beam activated (high beam possible)

 Circuit 15 ON Standing lamp and low beam activated (high beam possible)

 Circuit 15R ON Standing lamp activated

 Circuit 15C ON Standing lamp activated

 Circuit 15C OFF Exterior lights not activated

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Dipped beam

If the low beam is active, the following components are discretely actuated by the SAM control unit (N10):

 Left standing and parking lamp (E1e3)

 Right standing and parking lamp (E2e3)

 Taillamp and left parking lamp (E3e2)

 Right taillamp and parking lamp (E4e2)

 Left license plate lamp (S15/1e1)

 Right license plate lamp (S15/1e2)

 Xenon headlamp control unit (E1n1);

this then actuates the left low beam (E1e2)

 Xenon headlamp control unit (E2n1);

this then actuates the right low beam (E2e2)

If low beam is active, then the high beam (left high beam (E1e1) and right high beam (E2e1)) can be activated using the combination switch (S4).

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Standing lamp

If the standing lamp is active, the following components are discretely actuated by the SAM control unit (N10):

 Left standing and parking lamp (E1e3)

 Right standing and parking lamp (E2e3)

 Taillamp and left parking lamp (E3e2)

 Right taillamp and parking lamp (E4e2)

Tunnel passage special case

When driving into a tunnel, the automatic driving lights behave just as if "darkness" has been detected and they automatically switch on the low beam. When leaving the tunnel, the low beam is automatically switched off again.

Rain light function special case

If during rain or snow (even if "darkness" is not recognized) the wiper runs for 20 s with a cycle period of < 6 s (not "wipe" or "touch wipe"), the exterior lights are switched on depending on the circuit status.

If a new wiping cycle does not occur for another 20 s, then the exterior lights are switched off again. When switching off the wiper or in the event of a change of status to "circuit 15R OFF" then the exterior lights are switched off without delay.

 On vehicles with code (550) Trailer hitch, the SAM control unit (N10) places the respective signals on the CAN-B. The trailer control unit (N28/3) reads in the respective signals and actuates the trailer hitch socket (13-pin) (X58) accordingly.