Fog + Brights on pre 86 US models? - PeachParts Mercedes-Benz Forum

Johnhef · #1 01-22-2008, 10:53 PM

Anyone know if there's a conversion that will allow me to have my brights on with my fog lights? In particular this is on the 83 SEC. Later models 1986 and up as well as earlier euro spec models, this was able to be done, but US spec cars up to 1985 won't allow it.

In my mind I'm hoping its something simple as just moving the feed power wire to the fogs from one post on the headlight switch to one of the unused ones.

Has anyone done it? I could really use the extra light on the back roads around here at night.

mbdoc · #2 01-23-2008, 07:57 AM

In most states that is against the LAW.

You can always wire in a relay to turn them on.

75Sv1 · #3 01-23-2008, 09:55 AM

Maybe this will help:
http://www.jaimekop.com/240D/lights/
Aslo see Daniel Sterns lighting

lkchris · #4 01-23-2008, 12:10 PM

It's a silly idea.

When it's foggy or snowing, you never use your brights.

wbrian63 · #5 01-23-2008, 01:15 PM

Quote:

Originally Posted by lkchris

It's a silly idea.

When it's foggy or snowing, you never use your brights.

True, but when you switch on the hi-beams, you sacrifice some of the "up close" light in favor of seeing further down the road. The fog lamps do a good job of filling that void.

My '92 300SE allows for fog lights on in all 3 lighting modes - parking only, low beam & high beam.

If you're driving in really bad fog and turn on the high-beams - unless you're visually challenged, you'll learn quickly that low-beams is the way to go.

Johnhef · #6 01-23-2008, 10:52 PM

Wbrian63 hit the nail on the head.

Maybe you misunderstood my "silly question." I wanted to know how to make my '83 C126's fog lights work like the ones on my Euro 300TD, my 560SEL, my 300D and my R350. I said nothing about snow or fog, I just wanted more light at night on dark roads, see the last line of my original post. Maybe there arent any DEER in Alburquerque but there sure are a ton of them around here that like to jump out in front of cars.

75Sv1 provided a useful link- thanks, I'll look into that, or something similar. All I'm looking to gain is the way they were intended to function before conforming to the DOT of the 1980's.

I'm curious to know what states it's illegal in? How were they allowed then and now to sell those models there if the function is illegal? Like before mentioned, ever since 86 as far as I know, this function has been available.

Johnhef · #7 01-29-2008, 09:48 PM

Per the legality issue, I checked with some co workers and one guy said back in 96 when the 210's came out, they had a MB rep come down and show them the procedure to rewire the headlight switch to comply with the state's laws. This was in Virginia.

I however, did sucessfully rewire the fuse box in my 126 so my fog lights are unaffected by whether my brights are on or not. I followed the procedure provided in the link for the 123.

If that link ever goes dead, here's the description, with a few words changed to apply to a 126:

Fog light modification

A stock (Gen 1 US W126) is wired to supply power to the fog light switch only when the low beams are on. By changing the power supply for the fogs, you can run them anytime you like, even with the high beams. The power is fed by fuse number 6, which is a 16A (red) fuse. It also powers the right side low beam. By changing the power source to fuse 3 (left side parking lights), the fog lights have power with the parking light position on the switch.

Removing the fuse box to make this change can be a little intimidating. Be sure you DISCONNECT the battery first! There are two phillips screws holding the box in, and with a little work you can pull the panel out of it's housing. Be careful, damage to the wiring or fuse panel can be expensive to fix!

You'll notice that the connections to the back row of fuses is difficult to access, you may need to remove the connections to the opposite fuse in the front row. Make sure you remember where these wires belong and don't lose the screws! A magnetic tip screw driver is a must. The power for the fogs is gray with green and yellow marks (power for low beam is solid yellow). Clip the wire and use tape or some shrink wrap tubing to cover any of the wire that remains exposed. Carefully crimp/solder a new ring connector on the fog light wire and protect it with another piece of shrink warp. Then connect the wire to fuse number three, removing any wires you need to to gain access. The last step is to change the fuses. Swap the 16A from 6 with the 8A from 3. The fogs draw a lot of current, almost 8A by themselves. To help identify wires, you might want to get a copy of a Chiltons manual. They have a seperate schematic for the lighting system which is very useful.