Strange fog light and indicator behaviour on new mercs

[chriswt]

On Monday I was driving to work when coming the other way was a new CLK, as the driver switched on her indicator to turn left the left fog-light (just the one) also came on. Dodgy electrics I thought!

Yesterday I was approaching a mini roundabout when I saw exactly the same indicator/fog-light scenario happen to a new CSL as it was turning left at the roundabout.

Is this Mercedes attempt to rival the most stupid American idea of having a flashing brake light instead of an indicator.

 

[DansSlk]

On the front of the car thats totally normal.

Below a certain speed (can't recall from memory), with lights on and with a certain steering angle exceeded it pop's on the fog to help illuminate the corner.

 

[chriswt]

On the front of the car thats totally normal.

Below a certain speed (can't recall from memory), with lights on and with a certain steering angle exceeded it pop's on the fog to help illuminate the corner.

Thanks for that mate, my mind is at rest.

Personally I'd prefer a car that does its illuminating with its main lights . I can't see that a foglight is really going to make much difference but I bet it was an American that came up with that idea!!! However, I've never experienced the feature myself so I guess I'm not in the best position to pass comment.

 

[television]

Thanks for that mate, my mind is at rest.

Personally I'd prefer a car that does its illuminating with its main lights . I can't see that a foglight is really going to make much difference but I bet it was an American that came up with that idea!!! However, I've never experienced the feature myself so I guess I'm not in the best position to pass comment.

Its in their consumers menu, they can turn the feature off

 

[BTB 500]

There are a few previous threads on this ... technically it breaks UK law, where you're not permitted to have front or rear fog lights on unless visibility is under 100 metres. To avoid this some models allegedly change the light output when the foglight is being used as a 'cornering' light ... so it doesn't count as a foglight any more.

Personally I think it looks daft, and serves no useful purpose. On my in-laws' (German) R Class it seems to be triggered by steering angle rather than the indicators.

 

[Diesel Benz]

There are a few previous threads on this ... technically it breaks UK law, where you're not permitted to have front or rear fog lights on unless visibility is under 100 metres. To avoid this some models allegedly change the light output when the foglight is being used as a 'cornering' light ... so it doesn't count as a foglight any more.

Personally I think it looks daft, and serves no useful purpose. On my in-laws' (German) R Class it seems to be triggered by steering angle rather than the indicators.

It looks odd to me when only one of the fog lamps come on, like one bulb had failed. The intention anyway is to have a wider beam to the direction of turning. When you approach a turn, you may still be heading forward and the cornering lights would help seeing the road, like for pedestrians in the dark or what ever.

Odd too that an E-class is using fog lamp(s) for this, the W221 has a separate bulb for this purpose at the headlamp assembly. It does not look that odd at all then, and the beam is really helping visibility to the direction of turning, even if the car had active turning main beams. Then on the new CL they again use fog lamps for cornering illumination

 

[jaymanek]

The fog light will illuminate if the bulb for the indicator is blown...

 

[Diesel Benz]

The fog light will illuminate if the bulb for the indicator is blown...

You mean at the front, rear or both? I did not know this.
I guess it also blinks in this case, would be a difference from the cornering light function then.

 

[chriswt]

The fog light will illuminate if the bulb for the indicator is blown...

Almost all cars have that function!!!

Driving home at night I see plenty of cars with fogs on but unable to indicate.

A lot of cars also have a useful function whereby if the car/driver is stuck in the middle lane of the motorway then the rear fogs illuminate permanently.

 

[Matt45]

You mean at the front, rear or both? I did not know this.
I guess it also blinks in this case, would be a difference from the cornering light function then.

From personal experience this auto-standby function is very clever. My SL had a loose headlight cluster connector when the car was prepped for delivery. The first bulb to show failed was the left front indicator. The HUD told be it had failed and also told me the fog light was being used instead. Rightly enough the left front fog would flash in time with the others although the 'clicking' sound in the car was at double speed to indicate a fault with a bulb. By the time I got home all the left front lights were showing failed and the fog was doing everything. I think the car decides which is the most appropriate light to use in place of the failed bulb. The only lamp that doesn't get a standby is the wing mirror indicator. Likewise the rear brakes and rear lights have, I think, 3 bulbs so they always have a standby if one bulb fails. The car should tell you which has failed and in my case tells me which is being used to cover the failure. Bloody clever these Germans.

 

[pkS430]

Almost all cars have that function!!!

Driving home at night I see plenty of cars with fogs on but unable to indicate.

A lot of cars also have a useful function whereby if the car/driver is stuck in the middle lane of the motorway then the rear fogs illuminate permanently.

Additionally - another useful feature I have noticed is that the Front fog lights will illuminate if only the sidelights are working!! I think they detect an under 25 year old would be rally driver. They think of everything.

 

[BTB 500]

Speaking of foglights, I still find it a bit bizarre that they're disabled when the lights are on auto (at least, this is the case on my Vito). So if you're driving along in the dark and hit fog you need to move the knob from auto->off->side->main ... momentarily losing the headlights in the process!

 

[jaymanek]

You mean at the front, rear or both? I did not know this.
I guess it also blinks in this case, would be a difference from the cornering light function then.

front, not sure about rears... note that they dont flash at full intensity.. very clever really...

 

[robert.saunders]

front, not sure about rears... note that they dont flash at full intensity.. very clever really...

Indicator failure on the W203 I had, resulted in front fogs flashing as a temporary replacement, and at the rear one of the rear lamps did the same function (which also, I think if memory serves me, resulted in the opposite rear lamp cluster displaying different lamps in this situation to show a differentiation to those following). As stated, quite clever frankly

 

[Diesel Benz]

From personal experience this auto-standby function is very clever. My SL had a loose headlight cluster connector when the car was prepped for delivery. The first bulb to show failed was the left front indicator. The HUD told be it had failed and also told me the fog light was being used instead. Rightly enough the left front fog would flash in time with the others although the 'clicking' sound in the car was at double speed to indicate a fault with a bulb. By the time I got home all the left front lights were showing failed and the fog was doing everything. I think the car decides which is the most appropriate light to use in place of the failed bulb. The only lamp that doesn't get a standby is the wing mirror indicator. Likewise the rear brakes and rear lights have, I think, 3 bulbs so they always have a standby if one bulb fails. The car should tell you which has failed and in my case tells me which is being used to cover the failure. Bloody clever these Germans.

I believe the user manual even tells this for the rear lights but the fronts and specifically the turn signal backup was new to me (doesn't mean it would not be in the manual )

 

[Diesel Benz]

Speaking of foglights, I still find it a bit bizarre that they're disabled when the lights are on auto (at least, this is the case on my Vito). So if you're driving along in the dark and hit fog you need to move the knob from auto->off->side->main ... momentarily losing the headlights in the process!

Are you one of those "under 25 years old drivers"?

The way MB has implemented this makes it impossible to forget fog lights on (a real problem these days when it gets darker and rainy, even if other brands should have something similar on new models).

If you turn the light switch from off/auto directly to main, it would not turn off lights momentarily (the lights are not directly driven by the light switch).

 

[BTB 500]

Are you one of those "under 25 years old drivers"?

Sadly not, under 50 though!

The way MB has implemented this makes it impossible to forget fog lights on

I guess you mean you can't turn the lights off without cancelling the foglights in the process, but virtually all manufacturers do this nowadays. Either mechanically i.e. you can't move the light switch without disengaging the fogs, or electronically i.e. the foglight switch is a 'touch' type that resets when the lights go off if you haven't already turned the fogs off.

If you turn the light switch from off/auto directly to main, it would not turn off lights momentarily (the lights are not directly driven by the light switch).

At night the headlights most definitely do go off as you pass through the 'side' position on your way from 'auto' to 'main'. I've tried it, and I don't like it!

 

[BTB 500]

In fact, checking my handbook it actually says

If it is dark, only turn the light switch from auto to dipped beam when the vehicle is stationary. You could otherwise cause an accident if the headlamps were to switch off briefly.

So if you use the auto lights you're supposed to park if you encounter fog (bit tricky if you're on a motorway). Great design

 

[richard]

BTW, the fog lamp thing its called 'Cornering Lighting' and it comes enabled when you have Xenon lights on most of the new cars.

It can be turned on on cars without Xenon's depending on how good the person using Star is, and the age of the car.

I keep on meaning to do it on my ML because when its dark and you are turning slowly out of a junction there is almost no lighting of the sides of the road. I guess its less important where you live in a well lit city. I did it on my A class, and only got told once there was something up with my fog lights !


R

 

[BTB 500]

Do front fogs project a significantly wider beam close to the car than dipped headlights? I've tried it, and can't see any real difference in illumination out to the sides. And that's with the fogs on full power, which of course would be illegal as a cornering light in clear conditions