Xenon headlamp control unit, component description - GF82.10-P-2114TM

MODEL 211.0 /2 as of 1.6.06 except CODE (494) USA version except CODE (498) Japan version with CODE (614) Bi-xenon headlamp unit with CODE (618) Bi-xenon headlamps with CODE (621) Intelligent Light System (left-hand traffic) with CODE (622) Intelligent Light System (right-hand traffic)

MODEL 211.0 /2 as of 1.7.06 with CODE (494) USA version with CODE (614) Bi-xenon headlamp unit with CODE (622) Intelligent Light System (right-hand traffic)

MODEL 211.0 /2 as of 1.7.06 with CODE (498) Japan version with CODE (614) Bi-xenon headlamp unit with CODE (618) Bi-xenon headlamps with CODE (621) Intelligent Light System (left-hand traffic)

Fig 1: Locating Front Lamp Units And Xenon Headlamp Control Units

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Location

One xenon headlamp control unit each is located on the underside of the left front lamp unit and on the underside of the right front lamp unit.

Task

Bi-xenon lamp power control
Switchover from low beam to high beam
Actuation of automatic headlight range adjustment (HRA [LWR])
Actuation of active curve illumination (with code (621) Intelligent Light System (left-hand traffic) or code (622) Intelligent Light System (right-hand traffic))
Actuation of freeway lights (with code (621) Intelligent Light System (left-hand traffic) or code (622) Intelligent Light System (right-hand traffic))
Actuation of extended front fog lamp (with code (621) Intelligent Light System (left-hand traffic) or code (622) Intelligent Light System (right-hand traffic))

Function

The xenon headlamp control units operate as a master-slave combination and communicate with each other over Controller Area Network bus class D (diagnosis) (CAN-D).

The xenon headlamp control unit on the left front lamp unit is the master control unit.

Bi-xenon lamp output control

When switching on the low-beam function, the ignition modules of the left bi-xenon lamp with integral ignition module (E1e10) and the right bi-xenon lamp with integral ignition module (E2e10) are activated by the corresponding xenon headlamp control unit. These use a high-voltage surge to ignite the bi-xenon lamps. If an electric arc of sufficient stability is detected, the xenon headlamp control units switch over to power-output limitation mode.

When the freeway lights function is also switched on, the bi-xenon lamp optical power is increased over the xenon headlamp control units to 38 W.

Switchover from low beam to high beam

When the low beam function is active, the lower half of the light beam is covered up by a light distribution cylinder. When the high-beam function is requested, the xenon headlamp control units actuate the left light distribution cylinder motor (E1m3) and the right light distribution cylinder motor (E2m3); the entire light beam is now available for illumination of the road.

Actuation of automatic headlight range adjustment (HRA [LWR])

To correct the light range of the vehicle headlamps on vehicles without code (489) Airmatic (semi-active air suspension), the front axle level sensor (B22/2) data and the rear axle level sensor (B22/3) data are read in by the xenon headlamp control unit on the left front lamp unit.

The xenon headlamp control unit on the left front lamp unit evaluates them and makes them available to the xenon headlamp control unit on the right front lamp unit over CAN-D.

On vehicles with code (489) Airmatic (semi-active air suspension), the data on the vehicle level are sent by the Airmatic with ADS control unit (N51) over the Controller Area Network bus class C (engine compartment) (CAN-C) to the central gateway control unit (N93), which then routes them over CAN-D to the xenon headlamp control units.

The xenon headlamp control unit on the left front lamp unit correspondingly actuates the left headlamp range adjustment motor (E1m1), and the xenon headlamp control unit on the right front lamp unit actuates the right headlamp range adjustment motor (E2m1).

Actuation of additional functions for active curve illumination, freeway lights and extended front fog lamp (vehicles with code (621) Intelligent Light System (left-hand traffic) or code (622) Intelligent Light System (right-hand traffic))

The additional functions are realized by swiveling the headlamp unit or by continuously raising and lowering the light distribution cylinders on the light distribution cylinder motors.

The xenon headlamp control unit on the left front lamp unit actuates the left dynamic curve illumination motor (E1m2) and the light distribution cylinder motor, the xenon headlamp control unit on the right front lamp unit actuates the right dynamic curve illumination motor (E2m2) and the light distribution cylinder motor.

Following replacement, the xenon headlamp control units must be coded according to vehicle model, national version and master-slave function.

Signal inputs and outputs

Discrete inputs:
- Circuit 15 voltage supply
- Circuit 56b low beam
- Circuit 31 ground
Discrete outputs:
- Voltage supply of bi-xenon lamps with integrated ignition module
Controller Area Network signals:
- The xenon headlamp control units are participants of the CAN-D.
Local interconnect network signals:
- The xenon headlamp control units actuate over an internal LIN bus, the headlamp range adjustment motors, the light distribution cylinder motors and the dynamic curve illumination motors.