W115 fog light modification - PeachParts Mercedes-Benz Forum

79Mercy · #1 11-26-2009, 10:43 PM

I hope everyone had a good Thanksgiving this year.

I know people have modified the fog lights to run with parking lights and high beams on W123's. But my question is has anyone done this with a W115? How do i need to wire it so that i can run fog lights with parking lights. Fuse 11 controls the fog lights and fuse 8 controls parking lights. Has anyone done this before?

Thanks

compu_85 · #2 11-27-2009, 10:06 AM

You should be able to do the same procedure as the W123s... move the power wire for the fog lights from the low beam fuse to the parking light fuse.

How to figure out which wire is the right one? No diagrams? I'd use a test wire going to the battery and just apply power to the wires one at a time till you find it.

-Jason

79Mercy · #3 11-27-2009, 12:43 PM

The wire colors are the same as the W123. The foglight wire is gray with yellow and green dots. The yellow and gray wire(low beam) is also connected to fuse 11. So I guess i need to take the ring connector off the wires going to fuse 11 and just crimp on new new ring connectors, and then put the low beam wire back on fuse 11. Then connect the foglight wire to fuse 8 which is parking lights. I'll give it a shot.

79Mercy · #4 11-27-2009, 01:29 PM

I did it and it works great, i'll post pictures later. Tomorrow i'll do the same to my W123.

nhdoc · #5 11-27-2009, 04:58 PM

The reason the fog lights are on with the low beams and off when the high beams are on is because you are supposed to use them when it is foggy and when it is foggy it is actually harder to see using high beams because the light reflects off of the fog and all you do is light up the fog, not the road.

If you don't believe me try it next time you are out in the fog, turn on the high beams and see how hard it is to see the road. Believe it or not, the people who designed the car actually did it right...you use the fog lights with low beams and keep your high beams OFF in the fog...and when it is not foggy shut the fog lights off and use your low beams.

compu_85 · #6 11-27-2009, 05:00 PM

Only cars in the US are wired that way. In other countries you can have the fog lights on when you choose.

-Jason

#7 11-27-2009, 05:00 PM

I think the goal is to use the fog lights with only the parking lights.

nhdoc · #8 11-27-2009, 05:02 PM

Quote:

Originally Posted by compu_85

Only cars in the US are wired that way. In other countries you can have the fog lights on when you choose.

-Jason

The gray market cars I have had were all wired the same way, fog lights off with high beams...they were not changed for import.

79Mercy · #9 11-27-2009, 05:04 PM

Quote:

Originally Posted by nhdoc

The reason the fog lights are on with the low beams and off when the high beams are on is because you are supposed to use them when it is foggy and when it is foggy it is actually harder to see using high beams because the light reflects off of the fog and all you do is light up the fog, not the road.

If you don't believe me try it next time you are out in the fog, turn on the high beams and see how hard it is to see the road. Believe it or not, the people who designed the car actually did it right...you use the fog lights with low beams and keep your high beams OFF in the fog...and when it is not foggy shut the fog lights off and use your low beams.

I know that.

I just did it because it looks cool to only run the fog lights with parking lights. I didn't do it for the function.

BTW, Euro cars are wired like this. Mb designed it that way, but US DOT made them change it.

compu_85 · #10 11-27-2009, 05:06 PM

Gen 2 W126 cars are wired so the fog lights can be on w/ the parking lights, and do not turn off with the high beams.

-J