HFChristie

What does the Rear Fog light switch do? I think all it's doing on mine is turning on of the left (drivers) brake lights on, but that would look more like a faulty bulb to someone that serve any other purpose.

Thanks!

NYCGLK

It's not brake light, it is the rear fog light. It's on driver's side - just one. Please don't have it on when not necessary, it's super annoying to drivers behind you.

koalatm

This is how rear fog lamps work - they make it look like one tail lamp is lit up different than the other and the contrast between the pair allows better visibility of your vehicle for drivers behind you in foggy conditions.

eki912

And it shouldn't be the brakelight that is on, it should be separate one.
Allthough I haven't checked it on my own....

chuckmahon

Thank you for asking this (and answering ) - I finally tested the function and came to the conclusion that a light bulb was inop on passenger side - now I know the real story!

This is as quirky as a Saab

koalatm

Well, to be fair this is how rear fogs work on all vehicle makes - we just aren't used to them here in North America as rear fogs are not very common on our vehicles. Then you have people driving around looking like idiots with their fogs on in all conditions

HFChristie

I know that if I saw just one light on, I'd assume a malfunction.

My Porshce 928 has a feature where, if you turn the turn signal on (left or right) with the car off, the respective turn signal light illuminated, but didn't flash. This would be more of an alternate 4-way flasher than a fog light.

IMO, if they're going to call it a "fog light", it should be a separate light.

But, question answered - thanks

bop11

The set up HFChriste has is for European parking. It was normal for a person in Europe to leave the outside light on when parked at a curb a night. Older MB did this with the light switch.
The bright rear fog light is always on the driver side so a vehicle approaching from the rear knows on which side to pass.
NYCGLK is right! It seems every Volvo driver turns this on by habit even on a clear night. It is similar to people driving 55 mph in the rain with their 4 way flashers on.

NYCGLK

Those are called parking lights. You can do this on GLK, too with the light switch. There is position for L/R parking lights.

super7pilot

Having a rear fog light makes far more sense than a front fog light. Most if not all accidents in fog are the result of a driver not seeing a vehicle in front of them. And when a person sees that bright red light on a car in front of them they will normally associate it with a brake light and will slow down.