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

Model 257, 290 

up to model year 2021 

Shown on model 257 

Courtesy of MERCEDES-BENZ USA

Location 

The headlamp control units are located on the reverse side of the respective front lamp units.

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 work in a master/slave combination and communicate with each other via the peripherals CAN (CAN PER). As the master, the left headlamp control unit synchronizes the right headlamp control unit.

The headlamp control units have the following tasks:

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

Reading in of sensors and signals 

The input factors are read in via the following connections:

• Direct line 
• Peripherals CAN 

Direct line 

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

• Left rear level sensor (B22/7) (except code 459 (Steel suspension with adjustable damping) and except code 489 (AIR BODY CONTROL))
• Left front level sensor (B22/8) (with code P35 (Light package) and except code 459 (Steel suspension with adjustable damping) and except code 489 (AIR BODY CONTROL))
• Temperature sensors in left front lamp unit

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

• Temperature sensors in right front lamp unit

Peripherals CAN 

The headlamp control units read in the following function-relevant information via the peripherals CAN, among other things:

• Variant coding
• Terminal status of terminal 15
• Signal engine running
• Drivetrain operational signal
• Light function request
• Vehicle level (with code 459 (Steel suspension with adjustable damping) or code 489 (AIR BODY CONTROL) (left headlamp control unit only))
• Adaptive Highbeam Assist freeze frame data (with code P35 (Light Package))

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 headlamp control units actuate the following functions:

• Position lights
• Turn signal lamp
• High beams and headlamp flasher output
• Automatic headlamp range control (HRA) (left headlamp control unit only, Economic Commission for Europe (ECE) vehicles or with code 498 (Japan version) or with code P35 (Light Package))
• Cornering lights (with code P35 (Light package))
• Active curve lights (with code P35 (Light package))
• Active light distribution (with code P35 (Light package))
• Thermal management (temperature monitoring)

The front lamp units have temperature sensors that are used to sense the heat development in the areas actuated by the LEDs. The headlamp control units evaluate the signals from the temperature sensors. If the LEDs or the plastic housings of the front lamp units threaten to overheat as a consequence of high outside temperatures or high actuation currents, the headlamp control units reduce the LED actuation currents and thereby the level of heat development. The front lamp units are also ventilated. The active ventilation is also used at the same time for thawing or deicing at low outside temperatures.

Actuation of components 

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

• Direct line 
• Periphery CAN (with code P35 (Light package)) 

Direct line 

The left headlamp control unit actuates the following components via direct lines:

• Left high beam (E1e1) (except code P35 (Light Package))
• Left low beam (E1e2) (except code P35 (Light Package))
• Left front turn signal lamp (E1e5)
• Left front side marker light (E1e6) (with CODE 460 (Canada version) or CODE 494 (USA version))
• Left cornering light (E1e9) (with code P35 (Light package))
• Left front ambient light (E1e23) (with code P35 (Light package) (Economic Commission for Europe (ECE) vehicles only))
• Inner left position light and daytime running light (E1e28)
• Outer left position light and daytime running light (E1e29)
• Fan motor 1 for left front lamp unit (E1m4)

The right headlamp control unit actuates the following components via direct lines:

• Right high beam (E2e1) (except code P35 (Light Package))
• Right low beam (E2e2) (except code P35 (Light Package))
• Right front turn signal lights (E2e5)
• Right front side marker light (E2e6) (with code 460 (Canada version) or code 494 (USA version))
• Right cornering light (E2e9) (with code P35 (Light package))
• Right front ambient light (E2e23) (with code P35 (Light package) (Economic Commission for Europe (ECE) vehicles only))
• Inner right position light and daytime running light (E2e28)
• Outer right position light and daytime running light (E2e29)
• Fan motor 1 for right front lamp unit (E2m4)

Periphery CAN (with code P35 (Light package)) 

The left headlamp control unit sends requests for high beam light distribution via the peripherals CAN to the left front lamp unit LED matrix control unit (E1n11) and to the right front lamp unit LED matrix control unit (E2n11).

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

	Exterior lights wiring diagram	Model 257 up to model year 2021 except code P35 (Light Package)	PE82.10-P-2000-97XBA
		Model 257 up to model year 2021 except code P35 (Light Package)	PE82.10-P-2000-97XBB
		Model 257, 290 up to model year 2021 with code P35 (Light Package)	PE82.10-P-2000-97XBC
		Model 257, 290 up to model year 2021 with code P35 (Light Package)	PE82.10-P-2000-97XBD