The service manager told me that only driver side rear fog light lit up. I went home and open the tail light and found out that they are bulbs on both side. But only wire run thru the driver side not passenger side. Why only driver side lit up? I gonna hook up the other side. Anybody did this?

Where can I fine VFAQ for W203? Do we have one? I'm thinking about create one but don't know where to host?

In Europe only one rear fog light is allowed (on the driver's side) by law. This is so because it's hard to see brake lights coming on if there are already 2 x 21W bulbs shining from the rear of your car. In any weather condition, this is a major hazard to following traffic.

The single lamp has been the standard for well over 25 years in Europe.

If you ever use this light, MAKE SURE it is just in thick fog with under 50 m visibility, or blowing powder snow which is similarly limited visibility. I see a great many yobs using these lights in regular dry or rainy weather - all that shows is their lack of knowledge of the purpose of the lights. And perhaps their indifference towards the safety and comfort of drivers that follow them.

Don't connect the other one, it'll only make your car look like an Oldsmobile (you know, the one with the TWO rear fog lights in the rear bumper).

I wish M-B had some information on proper use of front and rear fog lights in the owner's manual.

all U.S. spec MB has only one rear fog light. i don't know the reason for it but that is the way it is. in Europe you can opt to have both rear fog light.

personally i think that one side of rear fog light is already enough. could be just me because i live in CA where we rarely have bad weather.

good luck on hooking up the left rear fog light...be sure to post a picture when you are done

Only one light because overtaking is only allowed on the left (driver's side). The bright fog light marks the left rear corner - no need to do it on the other side (they NEVER overtake on the right in Europe, at least in its civilized part, and it is strictly enforced and followed by all drivers). That setup would be reversed for the RWD world (GB, Australia, NZ, SA, etc.)

it is depending on the manufacturer because my dad's XJ-12 do have two rear fog light that are bright as hell. Volvo S90/960 also had two rear fog light.

Two rear fog lights look like brake lights. Long before the third brake light they made it standard for only one rear light for this reason, that way people would use caution, not stop if they saw one red light on the rear of the car in front of them. The light is on the drivers side for a physical reference of where the rest of the car is in bad fog. If you light up both sides you'll be doing more badthan good.

Mike T and mdp c230k have the correct interpretation of this. IMO, having only one light will get more attention than having two, which mimics standard brakelights, as others have said.

What gets to me is that while european cars lavish such attention to this confusing (to Americans) safety feature, they pay so little attention to the benefits of front and rear side marker lamps. The safety benefits of these are real, and the incremental cost of including them on euro-spec cars would be more than offset by the cost savings in standardizing bumper parts used worldwide.

Maybe so its only half as annoying when people drive around in clear weather with the rear fog lights on??

Oh, don't get me started about foglights (front or back) on in clear weather!

The FAQ's are here

All 850/S70 have only one, like the Benz. At least those destined for the US.

Actually, it is an excellent weapon against tailgaters - makes them first brake like crazy, then keep a distance from you.

Pulling over one lane and letting them pass and be out of your life is another option.

now that would be too easy wouldn't it?

I find that fogs in normal weather make a great idiot detector!

Can someone post a pic of this one-rear-fog-light phenomenon for us?

Thanks!

Tim

Those destined in Sweden as well...