Automatic headlamp actuation, function

P82.10-4021-09

Shown on vehicle as of 1.6.04 without code (494) USA version

1 Terminal status

2 Automatic driving light actuation activated in the instrument cluster

3 Rotary light switch in "AUTO" position

4 Darkness or rain detected

5 Terminal 61 ON

6 Engine speed

7 Position of combination switch

8 Actuation of standing lamp

9 Actuation of low beam

A1 Instrument cluster

B32/1 Automatic light switch daylight sensor
(up to 31.5.04)

B38 Rain sensor (up to 31.5.04)

G2 Generator

N3/10 ME control unit

N10/8 Rear SAM control unit

N10/10 Driver-side SAM control unit

N10/11 Passenger-side SAM control unit

N70 Overhead control panel control unit

N73 EIS [EZS] control unit

N80 Steering column module

S1 Rotary light switch

S4 Combination switch

CAN B Controller area network bus class B (interior compartment) (CAN B)

CAN-C Controller Area Network bus, class C (engine compartment) (CAN C)

B38/2 Rain/light sensor (as of 1.6.04)

E1e2 Left low beam

E1e3 Left standing and parking lamp

E1n1 Xenon headlamp control unit

E1n2 Xenon headlamp ignition module

E2e2 Right low beam

E2e3 Right standing and parking lamp

E2n1 Xenon headlamp control unit

E2n2 Xenon headlamp ignition module

E3e9 Left stop lamp, taillamp and parking lamp

E4e9 Right stop lamp, taillamp and parking lamp

E19/1 Left license plate lamp

E19/2 Right license plate lamp

Function requirements

 Rotary light switch (S1) in "AUTO" position

Function at start of journey (in darkness)

 Transmitter key removed:
exterior lights "Off"

 Circuit 15C:
exterior lights "Off"

 Circuit 15R:
standing lamp "On"

 Circuit 15:
standing lamp "On"

 Circuit 61 and engine speed > 300 rpm for t > 2 s:
standing lamp and low beam (high beam permissible) "On"

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Function at end of journey (in darkness)

 Circuit 61 and engine speed > 300 rpm for t > 2 s:
standing lamp and low beam (high beam permissible) "On"

 Circuit 15:
standing lamp and low beam (high beam permissible) "On"

 Circuit 15R:
standing lamp "On"

 Circuit 15C:
standing lamp "On"

 Transmitter key removed:
exterior lights "Off"

Function

Monitoring of the combination switch (S4) and the rain sensor (B38) as well as the automatic light switch daylight sensor (B32/1) or the rain/light sensor (B38/2) enables the driver-side SAM control unit (N10/10) to trigger the automatic driving light actuation. The rain sensor (B38) and automatic light switch daylight sensor (B32/1) or the rain/light sensor (B38/2) monitor the rain and light conditions in the direction of travel.

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Function when driving using the example of driving through a tunnel

The automatic light switch daylight sensor (B32/1) or the rain/light sensor (B38/2) signals the altered ambient light conditions to the overhead control panel control unit (N70). The overhead control panel control unit (N70) transmits via CAN-B (CAN-B) the signal "darkness detected" to the driver-side SAM control unit (N10/10).

The driver-side SAM control unit (N10/10) processes the signal "darkness detected" and the request signal "driving lamps On" is forwarded via CAN-B (CAN-B) to the passenger-side SAM control unit (N10/11) and to the rear SAM control unit (N10/8).

The driver-side SAM control unit (N10/10) actuates the left standing and parking lamp (E1e3) in the left front lamp unit and, via the xenon headlamp control unit (E2n1) and the xenon headlamp ignition module (E2n2), the right low beam (E2e2) in the right front lamp unit.

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The passenger-side SAM control unit (N10/11) actuates the right standing and parking lamp (E2e3) in the right front lamp unit and, via the xenon headlamp control unit (E1n1) and the xenon headlamp ignition module (E1n2), the left low beam (E1e2) in the left front lamp unit.

The rear SAM control unit (N10/8) actuates the left stop lamp, taillamp and parking lamp (E3e9) in the left taillamp and the right stop lamp, taillamp and parking lamp (E4e9) in the right taillamp as well as the left license plate lamp (E19/1) and the right license plate lamp (E19/2).

If adequate ambient light conditions are detected again, the driving and standing lamps are automatically switched off.

 The actuation of the low beam or high beam function depends on the position of the combination switch (S4).

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Function during wiper operation

If the rain sensor (B38) or the rain/light sensor (B38/2) detects wetting of the windshield, then the windshield wiper is activated according to the degree of wetting. If the windshield wiper is active for at least 20 s with a cycle time < 6 s the driving lamps are switched on as in the example described above.

If the cycle time is absent for 20 s, the driving lamps are switched off. With the functions of washing and one-touch wiping, the driving lamps are not switched on automatically.

When switching off circuit 15R or if the combination switch (S4) is set to the "0" position, the driving lamps are switched off immediately.