Headlamp Adjuster 126

[Placey]

My 500 SE has a pneumatic headlamp adjuster with a mind of it's own! I only noticed the problem when recently driving at night; when I step on the gas the headlamps go to full down position - making seeing almost impossible. When I back off, they return to level again. From the inside of the car, there is a hissing noise that can be altered by moving the selector to another position [it is quieter in position #1]. I have changed this switch [£30 no refunds] but this made no difference. I believe there is a one way valve in the pipe system that may be the cause. I have done a search but oddly enough, there was no word on this.

As this switch is a common addition to most mercs I would be grateful if someone can shed any light on it. For some reason, when I share this tale with anyone, they always laugh!

Thanks

 

[squirrell]

My 500 SE has a pneumatic headlamp adjuster with a mind of it's own! I only noticed the problem when recently driving at night; when I step on the gas the headlamps go to full down position - making seeing almost impossible. When I back off, they return to level again. From the inside of the car, there is a hissing noise that can be altered by moving the selector to another position [it is quieter in position #1]. I have changed this switch [£30 no refunds] but this made no difference. I believe there is a one way valve in the pipe system that may be the cause. I have done a search but oddly enough, there was no word on this.

As this switch is a common addition to most mercs I would be grateful if someone can shed any light on it. For some reason, when I share this tale with anyone, they always laugh!

Thanks

Hello,

The one way valve your talking about will be yellow and mounted near the drivers side fuse and relay box, there will be more than one and they will be connected to vacuum pipes entering the cabin. Light height pipes may have a purple trace, cant be sure.

The switch will hiss if there is a leak anywhere on its circuit and as the head lamps are moving up and down I suggest you look at the feed end.