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Home >> Mercedes Benz >> 2011 >> CL63 >> Repair and Diagnosis >> Electrical >> Motors, Switches, Relays >> Electrical System - Body - 216 Chassis - 1 Of 9 >> Basic Knowledge >> Headlamp control, function >> Headlamp control, function - GF82.10-P-2009SXA

Headlamp control, function - GF82.10-P-2009SXA

MODEL 216.3 up to Model Year 8 

MODEL 221.0/1 up to Model Year 8 with CODE (615) Bi-xenon headlamp unit with integrated curve illumination 

Fig 1: Headlamp Control Function Diagram - Shown On Model 221
G10112137Courtesy of MERCEDES-BENZ USA

Low beam, high beam, daytime running lamps, auto on/off headlamps, shown on model 221 

Low beam actuation 

Function requirement 

Function 

The upper control panel control unit reads in the position of the rotary light switch over the UCP [OBF] LIN and places the request on the interior CAN.

The front SAM control unit receives the request and forwards it directly over circuit 56b to the xenon headlamp control units. The xenon headlamp control units then actuate the relevant bi-xenon light.

High-beams actuation 

Function requirements 

High beam function 

The high beam actuation is requested by pressing the combination switch forward.

The steering column module detects the switch position of the combination switch and transmits the request over the chassis CAN to the central gateway control unit. It is then sent from here to the front SAM control unit over the interior CAN. The front SAM control unit actuates the high beam solenoids, whereby the partially covered light cones of the bi-xenon lights are completely released. In addition, on vehicles without code (610) Night View Assist, the high beams are actuated.

IMPORTANT For vehicles with code (610) Night View Assist, the left infrared lamp (E1e11) is installed instead of the left high beam and the right infrared lamp (E2e11) instead of the right high beam.

The status message "high beam actuation active" is transmitted by the front SAM control unit over the interior CAN to the central gateway control unit. The central gateway control unit then forwards it to the central CAN.

The instrument cluster receives the status message and then actuates the high beam indicator lamp.

Headlamp flasher function 

In contrast to the request for the high beam function, the combination switch is pulled to the rear and held there.

The function sequence and signal path for the headlamp flasher function is the same as for the high beam function.

The high beam actuation remains active as long as the combination switch is kept in the headlamp flasher switch position.

IMPORTANT If the low beam function is switched off on vehicles with code (610) Night View Assist, the bi-xenon lights are switched on and the high beam solenoids actuated accordingly, because infrared lamps are installed instead of high beams.

Daytime running lamps actuation 

Function requirements 

Function 

The daytime running lamps function is activated by the front SAM control unit. The front SAM control unit makes the request available on the interior CAN and at the same time actuates the front standing lights and, via the xenon headlamp control units, the bi-xenon lamps.

IMPORTANT The daytime running lights have a higher priority than the auto on/off headlamps.

In countries with statutory daytime running lamp regulations, only the headlamp flasher is permitted in daytime running lamp mode, but not the high beam. The high beam is only permissible when the driving lights are manually switched on using the rotary light switch.

Automatic headlamp actuation 

Function requirements 

Function at start of journey: 

Function at end of journey: 

Function while driving 

The overhead control panel control unit evaluates the signals from the rain/light sensor. When darkness is detected, the request is forwarded over the interior CAN to the front SAM control unit. The front SAM control unit sends the request to activate the standing lights to the interior CAN and actuates the front standing lights and the bi-xenon lights over the xenon headlamp control units.

Wiper startup function 

When the windshield wiper system is activated for min. 20 s with a wipe cycle of less than 6 s, the driving lights are switched on. If there is no wipe cycle for at least 20 s, the driving lights are switched off.

Automatic headlamp range adjustment (HRA [LWR]) 

Function requirements 

Function 

The automatic headlamp range adjustment (HRA [LWR]) serves to correct the headlamp range of the vehicle headlamps as a function of the load or the vehicle pitch motions induced by the vehicle dynamics.

For model 221 without code (487) Active Body Control (ABC), the data of the left front level sensor (B22/8), right front level sensor (B22/9) and the rear axle level sensor (B22/3) are read in by the AIRmatic with ADS control unit (N51), evaluated and made available on the chassis CAN.

For vehicles with code (487) Active Body Control (ABC), the data of the left front level sensor, right front level sensor, left rear level sensor (B22/7) and the right rear level sensor (B22/10) are read in by the ABC control unit (N51/2), evaluated and made available on the chassis CAN.

Information on vehicle speed is made available by the ESP control unit (N47-5) on the chassis CAN.

The information is made available by the central gateway control unit to the xenon headlamp control unit at the left front lamp unit (E1) over the front end CAN.

The xenon headlamp control unit processes all the information and forwards the corresponding correction data to the xenon headlamp control unit at the right front lamp unit (E2). The xenon headlamp control units actuate the left headlamp range adjustment motor (E1m1) and the right headlamp range adjustment motor (E2m1) accordingly.

IMPORTANT Both xenon headlamp control units operate in a master-slave combination, whereby the xenon headlamp control unit at the left front lamp unit has the role of the master control unit.

  Instrument cluster, component description A1 GF54.30-P-6000SX
  Rain/light sensor, component description B38/2 GF54.21-P-6000SX
  Lamp unit, component description E1, E2 GF82.10-P-2017SX 
  Xenon headlamp control unit, component description E1n1, E2n1 GF82.10-P-2114SXA 
  CDI control unit component description N3/9
Model 221 with engine 642
GF07.16-P-6000SX
  ME-SFI [ME] control unit, component description N3/10
Model 216 with engine 273.961
Model 221 with engine 272.965, 273.961
GF07.61-P-6000V
  ME-SFI control unit, location/task/design/function N3/10
Model 221 with engine 275.953/982
GF07.61-P-5000M
  Driver-side SAM control unit with fuse and relay module, component description N10/1 GF54.21-P-6010SX
  Description of components in ESP control unit N47-5 GF42.45-P-5118SX
  AIRmatic with ADS control unit, component description N51
Model 221 with code (489) Airmatic (semi-active air suspension)
GF32.22-P-5108SX
  ABC control unit, component description N51/2
Model 216
Model 221 with code (487) Active Body Control (ABC)
GF32.50-P-4501SX
  Overhead control panel control unit, component description N70 GF82.20-P-5216SX 
  Upper control panel control module component description N72/1 GF54.21-P-6040SX
  Electronic ignition/starter switch control unit (EIS) component description N73 GF80.57-P-6000SX
  Steering column module component description N80 GF54.21-P-6050SX
  Central gateway control unit, component description N93 GF54.21-P-4170SX
  Rotary light switch, component description S1 GF82.10-P-4106SX 
  Combination switch, component description S4 GF82.30-P-5000SX