I used to live in the Fulda Gap, eastern Hessen (old West Prussia) and we got fog there so thick you could not stand on a sidewalk and see 10 meters.

"Over there" you can get a ticket (fine) for using fog lights without fog or heavy snow. Sometimes I wish it were the same in NC!

For the REAR fog lights, there should be only one, and it's on the driver's side. The reason for this is stated by OldPokey - glare and confusion. If I recall correctly, the reason it's driver's side is industry standardization.

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1987 300D (230,000 mi on a #14 head-watching the temp gauge and keeping the ghost in the machine)
Raleigh NC - Home of deep fried sushi!

I thought that the tail fog light is only on the driver side only not both sides????

__________________
Current Garage
2008 Mercedes GL320 CDI 188k mi Repair/Work in progress
1994 S350 160k mi Garage Queen & prepping for repairs
2005 E320 CDI 203k mi Healthy & Daily Driver
1994 S350 357k mi Retried as parts car
1984 300TD 214k mi Blown OM617 Poss OM603 Swap??

Sold
1987 300SDL 200K+
1994 S320 181K mi
2008 E320 Bluetec 127k mi
1999 S420 130K mi
1980 240D 360k mi
15+ Others that has come, stay and gone

GONE, BUT NOT FORGOTTEN
1995 E320 SE 220k mi
1984 300SD 350k mi

MB originally set up these cars to have the rear fog light on the driver's side of the car. It is NOT illegal to have dual rear fog lamps in the US, so long as they are symmetrical about the centerline of the vehicle. (If it's a single rear fog light, it must be on the driver's side, or on the vehicle's centerline.)

If this were the case, my '95 Land Rover Discovery, my '04 MINI Cooper S, (and the Volvos I've owned) would be illegal. All of these vehicles (US market) were equipped with dual rear fog lamps from the factory.

There are studies out there that have shown that dual rear fog lights provide distance information that would not have been available with a single rear fog light on the driver's side. Perhaps this is why many vehicles have been changing over to the dual setup. And this is also why I elected to go with the dual setup as well.

I don't ever use my fog lights unless the conditions warrant it. I also hate it when people misuse their fog lights.

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Darren Asuncion
'81 300D Silver Blue metallic
'04 MINI Cooper S, Indi Blue w/ White roof
'94 Jeep Cherokee Sport, Flame Red
'95 Land Rover Discovery, Corallin Red

1.28.2018

I was just directed to this thread .

I just realized that last year I stumbled across a junked European market 230CE, I bet it had the correct rear harness for the Coupe....

Oops .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Regarding single vs dual rear fog lights I have only heard of a single light. It is placed on the overtaking side only. There is a socket available on each side to accommodate different countries/markets. When a vehicle is overtaking you the single fog light aids visibility and the location of the light orients your vehicle to the other driver. The assumption is that nothing else about your vehicle is clear except for that light. In the U.S. car guys will get it when they see a single brighter light on the left. Otherwise two bright red lights at the rear, anywhere in the world, are regarded as brake lights. Maybe two rear fogs are a thing now on production cars but it sounds like it would be a step back. Lots of threads about adding them on many makes/models but not sure about oe production.

My '91 300D has rear fogs on both sides. Glad to have them. Thick fog doesn't happen that often here in central NC, but in the summer we can get heavy thunderstorms that drop visibility to 10-15 yards. I'm amazed at how rain causes drivers to "lose their minds" and not give extra space between cars.

I wired in the rear fog on my '02 Golf as well. I firmly believe that the more visible you are in adverse weather conditions, the better chance you're gonna get home. IMHO, anyway...

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1991 300D 2.5 "Rocinante"
2002 Golf TDI "Teen Spirit"
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1984 300D
1966 Mustang I6 3sp
1985 Mazda RX-7 GSLSE
1982 Toyota Supra
1977 Datsun 280z
1971 Datsun 240z

As before, while a single rear fog is standard, two rear fogs on earlier cars tend indicate owner involvement. Twin bright red rear lights are essentially switchable constant brake lights. Without the beneficial data that a single fog light gives other drivers as far as orientation of your vehicle you could certainly add the third brake light to the switch if it's purely about being seen. A dual filament bulb would allow it to still act like a brake light.

This shows an American car in "export spec". They also make an observation that I did not consider. One rear fog makes a change in your other lights(braking) more discernible to other drivers. They state that two rear fog lights are allowed in most countries. Now I wonder what manufacturers have done it.

Rear Fog Lights

For anyone coming along in the future and using the information in this thread as a reference:

Based on empirical experience with a US 1985 300D, the information in the attached image from the original poster is incorrect. Specifically, the "NS" connection does not provide power. Rather, the foglights are powered via the "N" connection. This is confirmed both on inspection and via the applicable schematic in the M-B "Electrical Troubleshooting Manual".

Attached Thumbnails

 

This post is in reference to "Step 11" by the original poster.

To power the indicator bulb, the rotary switch MUST be in the following position:
A. Turned all the way to the right. That is, headlights on.
B. Pulled-out to the SECOND detent.

As for the bulb, I used an Osram 2721 (1.2W, 12V).

5cylinder,
I followed the OP's directions and the rear fog light mod works perfectly & the center indicator light lights up when rear fog is on.
I don't have the schematic in front of me but I think power gets transferred to the NS terminal when the switch is pulled out to the second detent for the rear fog. Anyhow, I followed his directions and rear fog works great!

I also did the OP's front fog light mod so they work with the parking lights or high beams.

Love both mods!