The full LED headlamp
Here you can find useful information and valuable tips on all aspects of replacing and adjusting an LED headlamp on a Mercedes-Benz W212.
Important safety note
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.
The following effects can occur if LED headlamps fail:
The following causes may be responsible for failure or malfunction:
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.
As part of control unit diagnostics, it is possible to employ the help of various functions and vehicle information as and when needed.
Before the headlamps can be adjusted, the following work must be carried out on the vehicle:
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.
The various diagnostic options are shown as examples by the mega macs 77 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.
Connect a diagnostic device and then set up a beamsetter in front of the vehicle.
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).
Following adjustment, confirm new values on the diagnostic device.
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.
In this video we show you how to professionally replace a full LED headlamp on a Mercedes-Benz W212 (model year 2014).
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, 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:
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).
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.
So as to avoid unnecessary delays while programming, photograph the LED code before beginning to mount the LED headlamp!
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.