Adjusting and replacing LED headlamps

Replacement of an LED headlamp

10037926a_AM0_white_inclined

The following information including service work shown is based on the example of a Mercedes-Benz W212 (model year 2014) but also applies to other vehicle models with identical component systems.

The following technical information and practical tips have been compiled by HELLA in order to provide professional support to vehicle workshops in their day-to-day work. The information provided on this website is intended for suitably qualified personnel only.

The full LED headlamp

Explode view — The full LED headlamp

Requirements for vehicle lighting are steadily increasing, a fact which places high demands on vehicle lighting systems. LED headlamps with innovative light functions are integrated into the technical systems of modern vehicle models. The functions are monitored by higher-level control units. Even a seemingly simple replacement of a headlamp requires special work steps in order to carry out a professional diagnosis and repair.

The following information including service work shown is based on the example of a Mercedes-Benz W212 (model year 2014) but also applies to other vehicle models with identical component systems.

System components

Range module / Vario-LED

Design:

Plastic lens
Lens holder
2*6 chip for LED light source
Vario roller with IHC+ functionality
CIPOS sensor system for the roller position

The 2*6 chip for LED module / range module generates a luminous flux of up to 2,765 lumens, whereby the road illumination optimally supports the driver with all the various light distributions.

Close range module

Design:

Lens/ reflector lens holder
Carrier frame
Harness assembly
Thermal sensor
Contact element+LED
Heat sink

The 5 chip module for the immediate road surface in front of the vehicle generates a luminous flux of up to 1,260 lumens, which achieves homogeneous illumination “at close range”.

FRA (Fahrtrichtungsnazeiger

LED FRA; Lichtleiterträger mit 8 LEDs und Sammellinsen.Das 5 Chip Vorfeld-Modul erzeugt einen Lichtstrom bis zu 1260 lm, wodurch eine homogene Ausleuchtung im „Nahfeldbereich“ erzielt wird.

Daytime running light / Position light top / Bottom

LED-DRL-PO light distribution, light guide technology.

LED cornering light

Bulb shield or cover for targeted illumination of the cornering area.

Control Unit (LCU) Light Control
Unit Control Unit (HLI max)

The light control units control various functions, such as light functions, SW fan/thermal management, Vario LED module functions, etc.

In addition, the control units – together with the vehicle system – regulate light distributions for the driving situation via the CAN bus using the Vario LED module.

(Roller) adaptive light actuator
(Height adjustment) vertical light actuator
(Dynamic cornering light / swivel function) curve light actuator

Fan headlamps

As is the case with other electronic components, the powerful LEDs with their enormous light output from a comparatively small chip surface must be operated within certain temperature limits. To this end, robust fans specially designed for headlamp technology are integrated in an intelligent thermal management system.

Checking LED headlamp

The LED headlamps or indeed vehicle lighting is monitored by higher-level control units. Any occurring errors are stored in the control unit's error memory and can be read using a suitable diagnostic device.

With some vehicle models, a warning message can also be displayed on the instrument cluster in the event of a system error. However, before control unit diagnostics are undertaken, it is first advisable to carry out a visual check on the individual system components as part of initial troubleshooting activities.

Control unit diagnostics

As part of control unit diagnostics, it is possible to employ the help of various functions and vehicle information as and when needed.

Replacing LED headlamps: Control unit diagnostics, error code — Figure 1: Error code

Replacing LED headlamps: Control unit diagnostics, parameters — Figure 2: Parameters

Replacing LED headlamps: Control unit diagnostics, actuator test — Figure 3: Actuator test

Error code

In this function, error codes stored in the error memory can be read. For subsequent troubleshooting, the error code description contains general information on possible effects or causes (Fig. 1).

Parameters

In this function, current measured values from the control unit can be selected and displayed for the various light functions (Fig. 2).

Actuator test

In this function, vehicle-specific headlamp functions can be controlled separately (Fig. 3).

Adjusting LED headlamp

Preparation for headlamp adjustment

Before the headlamps can be adjusted, the following work must be carried out on the vehicle:

Check tyre pressure and correct if necessary.
Check load.
Ensure correctly calibrated vehicle level; for vehicles that were previously raised, roll/drive them a few metres before adjustment so that the chassis "springs in".
Put the steering wheel in "straight ahead" position.
Close all doors.
Read off the vehicle-specific forward inclination, in this case 1%.
Beamsetter to be set up and aligned in front of the vehicle, i.e. in front of the headlamp

IMPORTANT

The vehicle and the beamsetter must stand on level ground (with the headlamp setting location in accordance with country-specific requirements).

It is recommended to connect a suitable battery charger to support the vehicle electrical system.

Adjust the headlamp using the beamsetter

The various diagnostic options are shown as examples by the mega macs X diagnostic device. The respective test depth and variety of functions can be set out differently depending on the vehicle manufacturer and these are dependent on the relevant system configuration of the control unit.

1

Carry out the following steps on the diagnostic device / vehicle

Connect a diagnostic device and then set up a beamsetter in front of the vehicle.

Select vehicle
Switch on the ignition
Read out and clear error memory
Select basic setting "Adjust headlamp"
Select zero setting
Switch on headlamps
Confirm zero setting. This sets the headlamps to the basic setting "Adjust headlamp".
Carry out headlamp adjustment, i.e. beam setting.

Replacing LED headlamps: Select basic setting \'Adjust headlamp\' — Select basic setting "Adjust headlamp"

2

Set the dial and light pattern

Set the dial of the analogue beamsetter to 1%. Mechanically adjust the light pattern in the horizontal position (reference line of height adjustment) or the vertical cut-off line to the O° line (Fig. 4).

With the digital beamsetter, use the proven vehicle and headlamp system selection. Select the forward inclination 1%. Then using the digital guide lines, mechanically set correct adjustment of light pattern (Fig. 5).

Replacing LED headlamps: Mechanically adjust the light pattern to the O line — Figure 4: Analogue beamsetter - mechanically adjust the light pattern in the horizontal position to the reference line of height adjustment or the vertical cut-off line to the O° line

Replacing LED headlamps: Mechanically set correct adjustment of light pattern — Figure 5: Digital beamsetter - using the digital guide lines, mechanically set the correct light pattern

3

Confirm new values

Following adjustment, confirm new values on the diagnostic device.

Replacing LED headlamps: Confirm new values on the diagnostic device - Fig. 1

Replacing LED headlamps: Confirm new values on the diagnostic device - Fig. 2

The following must be observed when mounting the led headlamps:

Secure vehicle to prevent automatic starting
Completely switch off the electrical system, remove the ignition key
Dismantle wheels, inner mudguards, bumpers
Disconnect electrical connections
Remove the headlamps
!!! ESD (electrostatic discharge) - guard against this when handling electronic components.
Attach the control units to the new headlamps at a separate workstation. Make sure that the connectors are correctly locked and that the seals are seated correctly. Observe tightening torques!
Adjust the height of the fixing banjo bolts between the old / new headlamp. When assembling, this is helpful in order to comply with the body gap dimensions/bumper headlamps.
Adaptation: in some cases it may be necessary to adapt the LED headlamp to the vehicle after mounting and before adjustment. In order to do this, a connection between the vehicle and the server of the vehicle manufacturer has to be set up. Connect the diagnostic device or VCI unit to the server in accordance with the manufacturer's specifications and follow the vehicle manufacturer’s instructions of use.

Repair instructions

Repair work on the lighting system in a vehicle may only be carried out by trained specialists. Repair work that is carried out incorrectly can lead to system failure and to severe personal injuries. For all repair work performed on the lighting system, please observe the safety and assembly instructions relating to the system in question and/or to those instructions provided by the relevant vehicle manufacturer.

Replacing headlamp control units – flashing / coding control units

After replacing the headlamp, individual components or the control units, it may be necessary to adapt or align the unit software to the respective vehicle periphery. Depending on the repair process, the LED code can be coded or new control units can be registered. These procedures are usually carried out online by means of a diagnostic device. This requires access authorisation to the online portal of the relevant vehicle manufacturer.

In our case study, the LED headlamp configuration is carried out, as an example, using a Hella Gutmann macsRemote diagnostic device and macsRemote Services.

Programming control units

Headlamp “flashing function” — Figure 1: Photo W212 headlamp “flashing function”

Headlamp “DRL function” — Figure 2: Photo W212 headlamp “DRL function”

Headlamp “LB function” — Figure 3: Photo W212 headlamp “LB function”

Headlamp “HB function” — Figure 4: Photo W212 headlamp “HB function”

Programming, also called flashing, is carried out remotely using a suitable diagnostic device. The prerequisite is a stable connection to the server of the relevant vehicle manufacturer.

So, for example, after replacing a control unit, the following procedures and programming functions are carried out.

After connection to the vehicle, first of all vehicle identification and the codes of the control units are queried. Following successful identification, initialisation of the new control units is performed. In this automated process, the hardware, software status and the variant of the control unit are recorded and matched to the vehicle.

Depending on the vehicle and system configuration, the following adaptations are carried out in order to achieve operational status:

Update of the basic software
Control unit variant
Adaptation of the VCD vehicle data record segments
- Low beam
- Active dynamic cornering light
- Motorway light
- High beam
- Fog light, extended
- Off-road light
- Daytime running light
- Warning light
- Direction indicator light
- Stepper motor parameters
- Light colour LED configuration
- Extended vehicle-specific data records

After successful programming, a test run is automatically carried out on the headlamp. In this reference run, the functions of the headlamp are tested (Fig. 01 to Fig. 04).

LED Code

W212 LED-SW “Front View” — Figure 1: W212 LED-SW “Front View”

“Prepare” W212 LED code LED code “watermark/ centre” — Figure 2: “Prepare” W212 LED code LED code “watermark/ centre”

W212 headlamp view/ please note_ positioning of LED code — Figure 3: W212 headlamp view/ please note_ positioning of LED code

The light colour of the LED lamps is also configured as part of the programming.

This function is necessary in order to optimally adjust the LED lamps of the new headlamp to the vehicle configuration.

The LED code is individually assigned to each individual lamp unit and appears on the headlamp housing. During programming, the LED code must be read and entered in the diagnostic application.

Important

So as to avoid unnecessary delays while programming, photograph the LED code before beginning to mount the LED headlamp!

Coding of further functions

MMI low beam setting for: Right-hand traffic — Figure 1: MMI low beam setting for: Right-hand traffic

MMI low beam setting for: Left-hand traffic — Figure 2: MMI low beam setting for: Left-hand traffic

MMI low beam light distribution, analogue: Right-hand traffic / asymmetry — Figure 3: MMI low beam light distribution, analogue: Right-hand traffic / asymmetry

MMI low beam light distribution, analogue: Tourist solution / symmetry — Figure 4: MMI low beam light distribution, analogue: Tourist solution / symmetry

MMI low beam light distribution, digital: Right-hand traffic / asymmetry — Figure 5: MMI low beam light distribution, digital: Right-hand traffic / asymmetry

MMI low beam light distribution, digital: Tourist solution / symmetry — Figure 6: MMI low beam light distribution, digital: Tourist solution / symmetry

Depending on the vehicle model and the region where the vehicle will be used, it may be necessary for the headlamps to be subsequently readjusted. Depending on the function, this can be done by the on-board electronics or by online support.

In this way, for example, country-specific requirements are adapted.

Country-specific requirements / regulations can involve, for example, the following switch-on conditions for the headlamp.

Light codes:

Daytime running lights switched on
Daytime running lights switched off
Daytime running light switched on + rear light switched on
Coming home, leaving home switched on
Coming home, leaving home switched off
Tourist light (driving in left-hand traffic with left-hand drive)

Not helpful at all

5

4

3

2

1

Very helpful

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