Automatic headlamp actuation, function - GF82.10-P-3003SKX

MODEL 171.4 with CODE (614) Bi-xenon headlamp unit

Fig 1: Automatic Headlamp Actuation Function Chart

Courtesy of MERCEDES-BENZ USA

Function requirements:

The rain/light sensor (B38/2) has recognized "night".
The exterior lamp switch (S1) is in position "AUTO".

The following combination applies at the start of the trip:

Circuit 15C OFF No illumination
Circuit 15C ON No illumination
Circuit 15R ON Standing lamp
circuit 15 ON Standing lamp
Circuit 61 ON Standing lamp and low beam

The following combination applies at the end of the trip:

Circuit 61 ON Standing lamps and low beam
circuit 15 ON Standings lamp and low beam
Circuit 15R ON Standing lamp
Circuit 15C ON Standing lamp
Circuit 15C OFF No illumination

The activation of the illumination is dependent upon the overhead control panel control unit (N70), which reads in the rain/light sensor (B38/2). The overhead control panel control unit (N70) supplies the signal to the Controller Area Network Bus Class B (interior) (CAN-B). The driver-side SAM control unit with fuse and relay module (N10/1) receives this message and actuates the xenon headlamp control unit (E1n1) and the xenon headlamp control unit (E2n1). The xenon headlamp control unit (E1n1) and the xenon headlamp control unit (E2n1) switch on the following lamps:

Left low beam (E1e2)
Right low beam (E2e2)

The driver-side SAM control unit with fuse and relay module (N10/1) switches on the following lamps:

Left standing and parking lamp (E1e3)
Right standing and parking lamp (E2e3)

The driver-side SAM control unit with fuse and relay module (N10/1) transmits, as the control unit responsible for the illumination, the message to switch on the driving lamps to the rear SAM control unit with fuse and relay module (N10/2).

The rear SAM control unit with fuse and relay module (N10/2) receives this message and switches on the following lamps via discrete wiring:

Left stop lamp, taillamp and parking lamp (E3e9)
Right stop lamp, taillamp and parking lamp (E4e9)
Left license plate lamp (E19/1)
Right license plate lamp (E19/2)

Special case in the daytime and bad weather

If the wiper is switched on in stage 1 (intermittent wipe), the wipe interval is < 6 s, and neither "wash" nor "touch-control wipe" are activated, the automatic driving lamps are switched on, even if the rain/light sensor (B38/2) recognizes "day".

The wiper has to be in operation for at least 20 s. If the wipe signal is absent for longer than 20 s, the illumination is switched off again.

The vehicle is approaching a tunnel

The rain/light sensor (B38/2) reports the dark tunnel entrance to the overhead control panel control unit (N70) and transmits the message "darkness" to the driver-side SAM control unit with fuse and relay module (N10/1) via CAN-B. The message is forwarded to the rear SAM control unit with fuse and relay module (N10/2) via CAN-B.

The driver-side SAM control unit with fuse and relay module (N10/1) actuates the illumination in the left front lamp unit (E1) and the illumination in the right front lamp unit (E2).

The rear SAM control unit with fuse and relay module (N10/2) actuates the illumination in the left taillamp (E3) and the right taillamp (E4), and the left license plate lamp (E19/1) and the right license plate lamp (E19/2).

The driving lights are switched on automatically, the vehicle drives into the tunnel with its lights on. The rain/light sensor (B38/2) continues to remain active in the tunnel and, as soon as it detects sufficient daylight in the tunnel exit, it initiates the driving lamps being switched off automatically.

Rain/light sensor, location/task/function	With code (345a) rain sensor	GF54.21-P-4123SK
Steering column module, location/task		GF54.21-P-4125SK
Lamp unit, location/task		GF82.10-P-4010SK
Taillamp, location/task		GF82.10-P-4020SK