General Information On Checking/Correcting Headlamp Adjustment - AH82.10-P-1000-01A
Model All (4xWD, CAR, Light transporter, smart)
General
The documents on headlamp adjustment describe the left side of left-hand drive vehicles. Unless a different description is given, the procedure for the right side is the same as for the left side. On right-hand drive vehicles, the procedure must be performed mirror-inverted.
On vehicles with level control and/or with dynamic xenon or LED headlamps, the engine must be running during the "Check/correct headlamp adjustment" procedure.
When checking the vehicle-specific headlamp adjustments the country-specific legislation and specifications from Mercedes-Benz AG must be observed.
The handling and application instructions provided by the device manufacturer for the country-specific approved headlamp adjusters must be observed (e.g. with regard to distance from headlamp adjuster to headlamp).
Otherwise it cannot be guaranteed that the headlamps concerned are correctly set, which can then jeopardize the road safety of the vehicle!
Identify chassis variants
Check if level control is installed on the front and/or rear axle in order to select the correct test prerequisites.
Test prerequisites
Before the headlamp adjustment is checked and corrected, the vehicle must be in a ready-to-drive condition.
Vehicle in ready-to-drive condition means:
- Correct tire pressure.
- Correct vehicle level including calibration and zero-position adjustment.
Additionally on vehicle with level control:
- Suspension at normal level.
Additionally on vehicle without level control and headlamps without dynamic headlamp range control:
- Vehicle unladen (on vehicles with attachments/installations not delivered ex factory, the specifications of the body/installation manufacturer must be taken into consideration!).
The test conditions and model series-specific instructions from the "Prepare vehicle for checking, correcting of headlamp adjustment" or "Prepare vehicle for checking headlamp adjustment at headlamp adjustment station" documents must be fulfilled!
Otherwise it cannot be guaranteed that the headlamps concerned are correctly set, which can then jeopardize the road safety of the vehicle!
Any additional operations required for correcting the headlamp adjustment must be taken from the corresponding operation items or applied subject to a separate repair order.
Checking and correction of the headlamp adjustment must be performed on a flat, horizontal surface.
Maximum permissible height difference of surface for:
- Vehicle: ±1 mm/m.
- Headlamp adjuster: ±0.5 mm/m.
These specifications are the minimum requirements of Mercedes-Benz AG. Any differing higher country-specific requirements must always be observed!
If the maximum permissible height difference of the surface is exceeded or the vehicle level is not correct, there will be a deviation (α) corresponding to the level difference (x) and wheelbase (y).
For example, on model 166.0 with a level difference of only 3 mm between the front and rear axles, this results in a deviation α of 0.6°, which results in a fault effect of approx. 0.1% during headlamp adjustment!
Deviation for level difference between front and rear axle on model 166.0
Deviation through level difference for different wheelbases between front and rear axles
Vehicle alignment to headlamp adjuster (01) on headlamp adjustment station
Position vehicle with front wheel left in direction of travel (05) at start of approach line (06) and parallel to approach line (06).
Drive vehicle forward with front wheel left in direction of travel (05) exactly along approach line (06).
The front wheel left in direction of travel (05) must always run at the same distance to the approach line (06) over the entire start-off distance (6.7 - 9 m) (A).
The vehicle must be correctly aligned on the headlamp adjustment station and the steering must be in the straight-ahead position.
This is the only way in which the geometric driveline axis of the vehicle will be aligned exactly with the light box of the adjustment device (01) guided on the guide rails (04) and correct headlamp check or headlamp adjustment is possible.
The distance of the rear axle to the approach line (06) is ignored due to the effects of different track widths on the front and rear axle, mixed tires and/or the drive line angle.
Vehicle at headlamp adjustment station
Headlamp version
For each specific model series, there is an ECE and SAE version for each headlamp variant (halogen, xenon or LED headlamps); different procedures for checking and correcting the headlamp adjustment are required for these different versions. The adhesive label (02) attached to the headlamp indicates whether the vehicle is equipped with ECE or SAE headlamps. Alternatively, it can be determined from the headlamp adjustment documents specific to the model series. In the example shown in the picture, the ECE version (03) is shown on the adhesive label (02).
Shown on adhesive label for model 166 with halogen headlamps in ECE version
Light-dark boundary
The dark area (c) and the colored area (b) of the light-dark boundary of the low beams must be above the reference lines, as shown in the color display. Only the light area (a) of the light-dark boundary of the low beams must be below the reference line, as shown in the color display.
The exact shape of the light-dark boundary of the low beams depends on the model series and the headlamps and is shown in the corresponding "Check/set low beams" documents.
Otherwise it cannot be guaranteed that the headlamps concerned are correctly set, which can then jeopardize the road safety of the vehicle!
Schematic diagram showing light-dark boundary