Headlamp Control Unit, Component Description - GF82.10-P-2020RDM

Model 172.4 up to model year 2017 

with code 640 (High-performance LED) 

with code 641 (Headlamps, LED, dynamic, left-side traffic) 

with code 642 (Headlamps, LED, dynamic, right-side traffic) 

Shown on model 172.4 

Location 

The left headlamp control unit is located on the underside of the left front lamp unit.

The right headlamp control unit is located on the underside of the right front lamp unit.

The headlamp control units are tightly screwed to the housing of the respective front lamp units. The headlamp control units are connected to the vehicle-side wiring harness via the front lamp units.

Tasks 

The headlamp control units operate in a master-slave combination and they communicate with each other over the chassis CAN 2 (CAN E2).

As the master, the left headlamp control unit synchronizes the right headlamp control unit.

The headlamp control units have the following tasks:

• Read in sensors and signals 
• Evaluation of input factors 
• Controlling functions 
• Actuation of components 

Read in sensors and signals 

The input factors are read in via the following connections:

• Direct line 
• LIN 
• Chassis CAN 2 

Direct line 

The left headlamp control unit reads in the signals of the following components over direct lines:

• Left active curve lights position sensor (E1b1)
• Left light distribution position sensor (E1b2)

In vehicles without code 483 (ADVANCED AGILITY package), the left headlamp control unit also reads in the signals of the following components via direct lines:

• Left rear level sensor (B22/7) via front SAM control unit with fuse and relay module (N10/1)
• Left front level sensor (B22/8)

The right headlamp control unit reads in the signals of the following components over direct lines:

• Right active curve lights position sensor (E2b1)
• Right light distribution position sensor (E2b2)

LIN 

The signals of the left front actuation module, LED exterior lights (E1n7) are read in by the left headlamp control unit via the left headlamp LIN (LIN G1).

The signals of the right front actuation module, LED exterior lights (E2n7) are read in by the right headlamp control unit via the right headlamp LIN (LIN G2).

Chassis CAN 2 

The signals are read in by the headlamp control unit via chassis CAN 2.

The functions that use these signals are described in the individual function descriptions (see block diagram or function schematic).

Evaluation of input factors 

The input factors that have been read in are evaluated by the integrated microprocessor and the relevant components are then actuated.

Controlling functions 

The following functions are realized by actuating the appropriate components:

• Low beam
• Daytime running lamps
• Turn signal lamp
• High beam and headlamp flasher
• Automatic headlamp range adjustment (HRA [LWR])
• Standing/parking lights
• Cornering illumination
• Intelligent Light System
• Adaptive High Beam Assist

Actuation of components 

The actuation of the components takes place via the following connections:

• Direct line 
• LIN 

Direct line 

The following components are actuated by the left headlamp control unit via direct lines:

• Left front side marker light (E1e6) (with CODE 460 (Canada version) or CODE 494 (USA version))
• Left cornering light (E1e9)
• Left front ambient light (E1e23) (except code 460 (Canada version) and except code 494 (USA version))
• Left Position light, daytime running light and turn signal light (E1e25)
• Left front position light (E1e31)
• Left headlamp range adjustment actuator motor (E1m1)
• Left active curve illumination actuator motor (E1m2)
• Left light distribution actuator motor (E1m3)

The following components are actuated by the right headlamp control unit via direct lines:

• Right front side marker light (E2e6) (with CODE 460 (Canada version) or CODE 494 (USA version))
• Right cornering light (E2e9)
• Right front ambient light (E2e23) (except code 460 (Canada version) and except code 494 (USA version))
• Right Position light, daytime running light and turn signal light (E2e25)
• Right front position light (E2e31)
• Right headlamp range adjustment actuator motor (E2m1)
• Right active curve illumination actuator motor (E2m2)
• Right light distribution actuator motor (E2m3)

LIN 

The left front LED exterior lights actuation module is actuated by the left headlamp control unit via left headlamp LIN.

The right front LED exterior lights actuation module is actuated by the right headlamp control unit via right headlamp LIN.

Exterior lights wiring diagram

PE82.10-P-2000-97TAC