Mercedes W124 Headlight problem

[ClassicMercs]

The offside dipped beam has given up. Its fine on sidelight - and OK on full main beam. But not working on dip.

I have tried in three bulbs (still have two from a recent change to better Osram bulbs). So the bulb shouldn't be the problem.

One day a couple of weeks ago the warning light flashed up for a few moments during use then went out. Then next time I went to use the lights it had failed - the warning coming on immediately.

I'm guessing it won't be a fuse and is probably wiring ? However, I'm rubbish at technical stuff. Any ideas would be greatfully received.

[PositronicRay]

Could be a fuse, worth trying 1st. The R129 has seperate fuses for each side dip and main.

[ClassicMercs]

Wouldn't have thought of that - but a Google suggests you could well be right - and if correct an easy fix.

Worse is if its the ground point behind the headlight - the control unit in the box behind the fuse box - or wiring itself. All sorts of potential if the fuse doesn't sort it.

Cheers for the pointer.

[PositronicRay]

ClassicMercs said:

Wouldn't have thought of that - but a Google suggests you could well be right - and if correct an easy fix.

Worse is if its the ground point behind the headlight - the control unit in the box behind the fuse box - or wiring itself. All sorts of potential if the fuse doesn't sort it.

Cheers for the pointer.

It won't be the ground point, all the beams share a common ground.

The schematic for the R129 is like this (which I believe is largely similar)

Dip switch>Fuse>lighting control module>Head lamp

You should have power @ the fuse (L&R will share this) so if its not blown check for power and then, it's a matter of checking wiring and control module.