[W126 Coupe] Headlights Beam Height Adjustment Switch - not working(560 Euro)

[Robert Karl Stonjek]

Dawid,
If the vacuum system fails then the lights drop down to their lowest point.  The vacuum gauge in the instrument cluster will not work either.  If the vacuum gauge does work then a previous owner may have disconnected the vacuum adjustment by blocking a vacuum line.

Find the main vacuum line going through the bulkhead in front of the fuse box.  You'll notice there is a kind of distribution system for the vacuum lines - they run to the headlight adjustment switch, the seat locks, gauge and vent controls.  Check the distribution units and see if there are any disconnected or blocked (check with the engine running - they will hiss when you disconnect them).

The switch for the headlight adjustment is a vacuum switch that is fairly straight forward to remove and inspect.  I don't recall the exact procedure, but I had the instrument cluster out at the time and I checked the light switch and the small globe that illuminates the controls at the same time.

I note that if the two vacuum lines to the switch are reversed then the switch does not work (yes, I did that by mistake :)

More clues: do the seat locks work (doors closed, engine running, seats should lock into upright position)?  If not then you might have more general vacuum line problems.

I'm about to adjust my headlights so that they are correct on vac switch position 1, so I can adjust up or down, but the manual says to adjust on zero.

Robert


> Hi,
> 
> The beam adjustment switch (next to the round lights switch on the  
> dashboard) does not work on my car (never has).
> If I recall correctly, I read somewhere that the car's Vacuum system  
> is also used to adjust beam height of the car?
> 
> Apart from it being something silly like a blown fuse (I am going to  
> check today, but I doubt it's that) - where should
> I start looking to fix this? I only ask because my lights seem to be  
> stuck in the lowest (pointing down / "heavy load")
> position, and I would like to raise them a bit for a further field of  
> view at night.
> 
> regards,
> Dawid
> The MB Coupes Website!
> W126 SEC Mailing List
> Postings remain property of MB Coupes, L.L.C.
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