Checking pneumatic headlamp range adjustment on standard headlamps - ra820b1404011x(4011)

WARNING: This page does not describe the selected car, but rather 42 other vehicles, including the 1999 Mercedes-Benz S600, 1999 Mercedes-Benz S500, 1999 Mercedes-Benz S420, 1999 Mercedes-Benz S320, and 1999 Mercedes-Benz CL600. However, it is still accessible from the selected car via links, so may be relevant.

B. Function Model 140

Preliminary work:

Front lamps adjusted (Maintenance manual volume 3).

B. Function

NOTE: The headlamp range adjustment is not fitted to cars with hydropneumatic suspension as vehicle level is adjusted by the hydropneumatic suspension, e.g. depending on car load.

The headlamp range can be adjusted with the regulating switch (1). The headlamp is adjusted by vacuum-operated positioning elements.

Fig 1: Identifying Regulating Switch

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

The pneumatic lines (2) are installed on the regulating switch (1) with quick connectors or shrink-fitted as of approx. 10.93. A shut-off valve integrated into the regulating switch (1) closes if the vacuum drops preventing the position of the reflectors from changing. The regulating switch (1) is supplied with vacuum from the intake manifold via the vacuum distribution block.

Fig 2: Identifying Pneumatic Lines And Regulating Switch

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

There is a positioning element (3) on each lamp unit with a maximum stroke of 3.0 ± 0.2 mm. The positioning element is connected to the swivel-mounted reflector by a pull rod.

Fig 3: Positioning Element

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

The regulating switch (1) has not only the basic position "0" but also the range control settings 1, 2 and 3. In the basic position "0", the maximum vacuum exists at the positioning element (table) and holds the reflector in its basic position. In the range control stages 1, 2 and 3, a lower vacuum exists at the positioning element (table). The stroke is increased and the reflectors are tilted down out of the basic position (see table for range of adjustment).

Fig 4: Identifying Regulating Switch

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

RANGE CONTROL DEPENDING ON LOAD OF CAR

Position of regulating switch	Load state
0	Front seat or seats occupied
1	Front or rear seats occupied
2	Front or rear seats occupied and load in trunk up to permissible rear axle load or
3	Front seats occupied and max. load in trunk (max. permissible 100 kg); if required when hauling a trailer.

Position of regulating switch	Adjustment range at positioning element in mm	Vacuum in mbar
0	0.0	400 ± 30
1	0.95	290 ± 30
2	1.70	200 ± 30
3	3.00	50 ± 30