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Discussion Starter #1
I had my fog lights (front and back) on last night as it was very foggy at the coast. A friend driving behind me said it looked like one of my brake lights was burned out. When I checked, it was my right rear fog light that was not working. Then when I checked the front, neither fog light was working.

I don't have the headlights on "auto". I have them turned all the way to the right for low/high beam and then pulled them out two clicks for both front and rear fog lights.

Is there something I am not doing or do I just have bad bulbs? It seems strange that 3 out of 4 would be bad on a new car.

Also, when my headlights are on, the rear lights only have a thin line of light in the middle for the rear tail light. Not very easy to see at night. Is there supposed to be more of the tailight lit than that?
 

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Well, you don't have a problem with the fog lights on the rear lenses. That is how it is supposed to be when you have the light switch all the way to the right and pulled out. Only the REAR left side is equipped with that special bulb which makes it look like one is burnt out, I dunno if its for backing up or what. During delivery the dealer went over this point alot, so I didn't think I had a burnt out rear right fog light.

The rear lens appearance is correct too (with respect to the thin line). I think your car is fine.

To make it just so the front fog lights are on, push in the switch one click, if you have it all the way out, or pull out one click from a fully depressed position, all of which is when switch is all the way to the right.
 

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Discussion Starter #3
roadsterboy - 3/11/2005 4:16 PM

Well, you don't have a problem with the fog lights on the rear lenses. That is how it is supposed to be when you have the light switch all the way to the right and pulled out. Only the REAR left side is equipped with that special bulb which makes it look like one is burnt out, I dunno if its for backing up or what. During delivery the dealer went over this point alot, so I didn't think I had a burnt out rear right fog light.

The rear lens appearance is correct too (with respect to the thin line). I think your car is fine.

To make it just so the front fog lights are on, push in the switch one click, if you have it all the way out, or pull out one click from a fully depressed position, all of which is when switch is all the way to the right.
Thanks, then my rear lights are ok. But why would you only have a fog light on one side in the rear???

But my front fogs must be broken as they do not come on when I pull out one click from a fully depressed position and the switch is all the way to the right[:(]
 

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malibuite - 3/13/2005 11:06 AM

I had my fog lights (front and back) on last night as it was very foggy at the coast. A friend driving behind me said it looked like one of my brake lights was burned out. When I checked, it was my right rear fog light that was not working. Then when I checked the front, neither fog light was working.

I don't have the headlights on "auto". I have them turned all the way to the right for low/high beam and then pulled them out two clicks for both front and rear fog lights.

Is there something I am not doing or do I just have bad bulbs? It seems strange that 3 out of 4 would be bad on a new car.

Also, when my headlights are on, the rear lights only have a thin line of light in the middle for the rear tail light. Not very easy to see at night. Is there supposed to be more of the tailight lit than that?
G'day Malibuite,

The rear foglamp is only actuated on the driver's side (see page 110 of the US Manual). Same in Oz.

However, your front ones should be working; as you say, it seems unusual that both front bulbs should have blown already. In fact, page 363 of the US manual indicates that you should get a warning message if either front fog lamp is malfunctioning!

According to pages 380 & 381 of the manual, the tail (and brake) lights (LEDs) are only in the lower red section of the rear light assembly.

Cheers,
....Julian
 

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I really don't understand what purpose that left rear fog light serves, at 1st I thought it was to assist in backing up for left hand drives, but that seems to be useless for that purpose. The problem with the front seems to be a mystery.
 

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My guess is the reason for just one fog light on the drivers side, although it seems odd and wrong, is exactly that, it seems wrong. I believe it is to alert other drivers behind you in fog. WHile I don't completely agree, I think this is why there is only one. To make drivers behind you in fog say "what is that in front of me, it looks strange."
 

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Discussion Starter #7
bmwnomore - 3/11/2005 6:59 PM

My guess is the reason for just one fog light on the drivers side, although it seems odd and wrong, is exactly that, it seems wrong. I believe it is to alert other drivers behind you in fog. WHile I don't completely agree, I think this is why there is only one. To make drivers behind you in fog say "what is that in front of me, it looks strange."
Obviously the designers did not live in Southern California where nothing is thought of as strange. However, my friends did notice it even if they thought my brake light was out.
 

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I agree. People will probably take more notice if there is just one bright light. Whether or not every driver recognises a single red light as a fog light is another question.
What I was wondering was why front fog lights aren't yellow these days? I heard someone say that the yellow light had a longer wavelength, and therefore penetrated fog better than white lights. Is this a load of garbage?
 

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Not sure about the yellow. I'm glad they're not yellow. The yellow side markers are more than I can bear. But, like Malibuite said, it was noticed by someone behind her. I'm pretty sure that's why there's only one. I had the same thing happen to me when I first got the car. I put on both fog lights and went out to dinner with a friend who had his big bad Vette. When we got to the restaurant he said "Hey, that german crap has a rear tail light out already!" I had no idea there was only one fog light so I thought he was right. I guess the laughs on him. I'm sure it will be one of the only times he'll see MY tail lights!
 

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Discussion Starter #10
two dogs - 3/11/2005 6:42 PM

malibuite - 3/13/2005 11:06 AM

I had my fog lights (front and back) on last night as it was very foggy at the coast. A friend driving behind me said it looked like one of my brake lights was burned out. When I checked, it was my right rear fog light that was not working. Then when I checked the front, neither fog light was working.

I don't have the headlights on "auto". I have them turned all the way to the right for low/high beam and then pulled them out two clicks for both front and rear fog lights.

Is there something I am not doing or do I just have bad bulbs? It seems strange that 3 out of 4 would be bad on a new car.

Also, when my headlights are on, the rear lights only have a thin line of light in the middle for the rear tail light. Not very easy to see at night. Is there supposed to be more of the tailight lit than that?
G'day Malibuite,

The rear foglamp is only actuated on the driver's side (see page 110 of the US Manual). Same in Oz.

However, your front ones should be working; as you say, it seems unusual that both front bulbs should have blown already. In fact, page 363 of the US manual indicates that you should get a warning message if either front fog lamp is malfunctioning!

According to pages 380 & 381 of the manual, the tail (and brake) lights (LEDs) are only in the lower red section of the rear light assembly.

Cheers,
....Julian
You read the manual??? [:0][;)][:D]

Every time I pick it up I get discouraged by its size and out it back down. However, I am going to make a real effort to look at it this weekend. But my front fogs are not working and there is no warning message. I only have 180 miles on the car so may have to take it in before its 1000 mile checkup.
 

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maibuite:

The rear fog light is functioning just as it does on many cars, even non mercedes....all I have seen have just the one side rear fog lamp, volvo, bmw, etc. It is common and meant to just show up further and make people take notice. Your front fog lights however, are a mystery. When the lights are on (turned clockwise to the right and the switch is pulled out a notch, they should illuminate...also, at the switch in the car, do you have a second round green dot around the switch lit? that indicates the fog lamp...have you tried in front of a building where the reflection lets you see it? If they aren't operating, have the dealer fix it...[:D][8D][:D]
 

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Zman - 3/12/2005 9:16 AM

Explanation here:

http://lighting.articles.*/rearfogs/

replace * with m b z . o r g
That doesn't explain why only one side is wired up. In fact it's even more confusing, since it would cost no more for the manufacturer to make both lights work (except for the cost of a bulb).

The official explanation which I read somewhere is that a German road safety survey found some years ago that one bright rear foglight was actually more effective than two, from the point of view of another vehicle approaching from the rear. I don't fully understand this, except that a single bright red light can't easily be mistaken for a pair of brake lights. It's extremely common for German cars to only have one foglight, and it's not for costcutting reasons.

In the past, with several cars, I've made the other one work myself by running a wire across the car and adding a bulb. That depends how much of the hardware is there, of course. If there's no bulbholder, then it's not worth it. Also, the wire may not be needed, if the wiring loom already has the power for the lamp.
 

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Had my Dad reading over my shoulder, for this thread and his explaniation as to why there is only one fog light - is so that drivers behind you do not think that you are just braking. [8D] (He did use to be a used car sales man!!! [:eek:)])

I don't know what it's like for other countries, but in my neck of the woods - it is quite common for drivers to forget to knock their fog lights off when the fog is gone, and a number of times I've been behind a car and thought - damm they're braking a lot. Only to then realise they've still got their fog lights on!!! [}:)]
 

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Good explanation Bev...everyone is coming up with good rationelle...[:D][:D][:D]
 
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