regardless, when the light switch is in the "O" position (MB, that typically means OFF) then the headlights should NEVER react on their own. I don't care what time it is or where the #$%^ sun is located.

To paraphrase - OFF means OFF.

 

Fully agree but it looks like the engineer who designed the M-B light swith has a different opinion.

To him "0" means "Not Active" or "Not Available".
Maybe they forgot to connect the wire to the "O"?

 

I was on the road yesterday at around 10am. Bright sky, not a cloud to be seen. My car: US model, DRL option ON, headlight switch in "O" position.

. Drove car to a business. No problems
. Started the car when leaving - headlights came on.
. Headed for an MB dealership about 5-7 miles away.
. Got within 1/2 mile of the dealership, fricken lights go out.
. drove past the dealership heading for home, within 1/2 mile the lights came back on!
. rerouted back to dealership, 2 blocks away lights go off.
. stopped at dealership anyway.
. gave my story to the SM, he never heard of this malfunction. Of course since the lights were now off I had no proof.
. SM looked at the option menus on my car and turned off the "Delay" option I had set for turning off the headlights. Just an idea he said.
. Drove home with no light malfunctions.
. After dark, started car for a short trip, headlights came on and stayed on...switch was still in the "O" position. Regardless of what position I moved the switch the lights remained on.

Back in the garage this morning, unable to turn off lights with switch, EXCEPT when in the "parking lamps, license plate and instrument lighting" position (position 5 US model) - headlights then went off and parking lamps on.

. headlights on even when switch in the left or right "standing lamps" position (position 1 and 2 US model)..

any one know where the light/daylight sensor is located on the vehicle? I'm thinking I can cover it to simulate the last problem noted above when I return to the dealer.

 

eeferber.
The M-B Tech told me the light sensor in located within the rear-view mirror cluster on the wind shield.

So after the change is your auto-light behaving as designed?

 

nope, no change at all. Still malfunctioning as before.

edit: oops, better define for me exactly what you mean by "auto-light"...

 

Here is my definition of "auto-light":

1. When it's dark (the light sensor detects that the lighting level is low) the headlights switch on automatically.
2. When you drove under a tunnel or inside a garage (underground) the headlights switch on automatically.
3. The instant the sensor detects that you are driving in daylight (bright sunshine) the headlights swith off automatically.

The light switch functionality is a separate issue.
As per normal design the "0" position should switch OFF the headlights leaving the DRL ON.
You should then be able to manually switch ON or OFF the headlights as you see fit giving you the driver total control.

The flaws in the M-B auto-lighting involves two issues:
1. The light switch does not work as designed. You cannot manually switch ON/OFF the headlights. You have no control. It is set to "Auto" only.
2. The light sensor sending commands to the lighting malfunction at random. In bright daylight it would often switch on the headlights when it shouldn't have. This happens at all times of the day. You cannot turn off the headlights when this happens.

The underlying fear is one night if you're driving on an unlit interstate highway and the auto-light fails to switch ON the headlights and the switch does not allows you to manually turn on the headlights you could be in a life threatening situation since you have no control of the lighting.

This is unacceptable for any vehicle much more so in an "expensive" "luxury" brand like a Mercedes-Benz.
I don't know why so many others are not complaining to their dealers and getting M-B involved to fix both the light switch as well as the auto-lighting and the ability to manually tuen ON/OFF the headlights.

Having Auto-lighting is a nice and convenient feature but there should be a manual override like the automatic transmission or the automatic climate control.

 

If you mean 'Yes', press 'No' - it is how it was designed ...

 

found what I think is the light sensor. It's visible from outside the vehicle, located essentially where the rear view mirror attaches to the windshield.

At least with US cars we can turn off the DRL option, which seems to me to be the trigger for all of this bizarre behavior. Unfortunately you Canadian owners can't do this.

When I turn off DRL ALL the weird light behavior is eliminated on my car.

 

But the LED DRL are what makes the 2011 ML cool looking and more up to date so it's nicer to have them on during the day time.
The 2012 ML also has these LED DRL so I am really curious to find out if it has the same issues!

 

just inquiring if anyone has had any more interaction with their dealer attempting to fix this problem?

I'm taking my ML in for service early next week and would like to be prepared to help my dealer diagnosis this, especially to eliminate a bunch of unnecessary switch/sensor replacements.

 

No further developments to report.
You should still bring this issue up so that M-B will be aware that there are more cases of the auto-lighting not functioning properly.

Good luck.

 

I also have this problem.i wonder if thrre is a way to change the sensibility of the daylight sensor?

 

DRL option ON, headlight switch in "O" position.

I've bought my ml 5 oktober 2011, so recently here in BELGIUM-and ist has the same problem- hopefully mercedes germany engeneers will tackle the problem.
Could the sensor not be programmed in sensibility to light events?
Is there no way to alter the sensibility of the daylight sensor by servicing the car at the dealer.

Would like to have an answer of an interested engineer??
thanks

 

Hi Idemolder.

Is your ML a 2011 model or 2012?
The auto-lighting issue affects both GL & ML SUVs and looks like a design flaw.

I don't think the light sensor is the cause.
M-B should redesign the light switch so the the OFF "0" position will actually switch off the headlights.

You should also ask your dealer to look into finding a solution.

Cheers

 

That's the rain sensor. I believe the light sensor is in the back of the rearview mirror.

 

It must be a 2011 model. There is no "0" position in a 2012 model, only "AUTO" position. Seems like MB engineers guessed something is wrong...


No. The light sensor is really located where the rear view mirror attaches to the windshield. I tried to cover this place and headlights immediately came on. After I uncovered it, the headlights came off and DRL turned on. Try it for yourself.

 

you're probably right about that, but it's still in the same general area. When I put a towel/rag across the windshield in that area I can cause the headlights to come on (with the switch in "O").

 

LOL! Looks like the auto-lighting issue may also be carried over to the 2012 ML! M-B engineers seems to bury their heads in the sand or adopt the attitude that "It's working as designed"!

If that is the case I'll just have to put up with this untill my lease is up in 2013 and then decide if I want to buy over my ML or get the W166 if the auto-lighting is resolved or get the new X5 Diesel.

I'll post on the W166 forum to see if any of the new owners have this issue.

 

Wondering how many here have had their dealer contact MB Technical Support and have a case report opened on this problem? Until there are a number of official cases opened with MB Technical we have no chance of MB allocating any resources to resolving this problem.

I had my dealer do the above - MB Tech claims no prior knowledge of this problem. I'm not completely shocked by this as I don't think they would necessarily admit it even if they did.

Took my car in for a scheduled service and was easily able to recreate every one of the problems/conditions we've discussed here. When I picked up the car later in the day, the service manager was pretty straightforward...since it doesn't represent a true safety issue chances don't get my hopes up that it will be fixed any time soon (or ever). I think this is especially true since MB has moved on to the W166.

I'm disappointed, but as this is the only issue of any kind I have thus far with my vehicle I guess I can live with it.

 

This morning my ML was due for the 30,000 KM Service B and as I set off on the 17 KM trip to the M-B dealership my headlights came on and stayed on all the way to the dealership even though it was bright sunshine with blue sky!

When I arrived I asked the SA to get the Tech to check my ML which I left with the engine on and the headlights on.
The Tech was the same one who changed my light sensor the first time I sent my ML in to fix the erractic auto-lighting behaviour.

He said he has made some research and found an internal article which dealt with this issue and unfortunately while M-B is fully aware of this issue since 2009 there is no fix!
This issue also affects numerous M-B models!!!

I've got a copy of the document which I'm reproducing below:

DRIVING LIGHTS SWITCH OFF TOO LATE OR ON TOO EARLY (BLUE SKY EFFECT).

Topic number: G182.10-P-009466
Validity: Models 203 (06/2003), 169, 245, 215, 216, 209, 219, 211, 164, 251, 220, 221, 230, 171. With rain/light sensor (RLS).

COMPLAINT:
The customer complains that, under a cloudless, blue sky (away from direct sunlight), the driving lights switch off too late when the rotary light switch is in the "Auto" (automatic) position.

In addition, when the sun is low in a cloudless, blue sky, the driving lights switch on too early when the rotary light switch is in the "Auto" (automatic) position.

CAUSE:
Under a blue sky, the sensor interprets the ambient brightness as being too dark due to its physical operating principal (Blue Sky Effect). The reason for this is that the sensor measures light in the infrared range, and range of light occurs less than usual under a cloudless sky.

REMEDY:
Please advise the customer of the technical limitations in this special situation.

NOTE:
Replacement of the rain/light sensor (RLS) is not justified and does not remedy the complaint.

To me it's a design defect which M-B has no solution and is doing nothing to rectify.

As I mentioned in my earlier posts that the auto-lighting feature on my other car BMW 335d works flawlessly for the past 75,000 KM and not a single incident of maulfunction even in Blue Skies and bright sunshine.

Even my older vehicles like a 2008 Honda Accord and a 2007 Suzuki Grand Vitara the auto-light worked as designed flawlessly.

So if the Japanese and rival BMW engineers can get this right why can't M-B?

What a major let down by M-B!

 

I,personally,couldn't care less how well or poorly the automatic headlight feature works.Yes,I can see one potential use for it in *my* life....a long trip on an Interstate during which the sun is sure to rise or set.But otherwise I WANT CONTROL OF MY HEADLIGHTS! My BMW allowed me to have control.Are you listening,Mercedes? Tune out the voices of your damn lawyers and do the right thing.

OK,stepping off my soapbox now and reaching for my blood pressure pills!

 

This morning at the same time as yesterday (8.00 AM) the Auto-lighting behaved itself and switched on the headlights when I drove under a highway under-pass but switched off the headlights when I exited into daylight. Yesterday in bright blue sky the headlights came on for the duration of my trip to the dealer!

The difference was today the sky is gray and NOT Blue! But the sun was shining as bright as yesterday.
Also the sun angle was like 15 deg (low) which dispelled the M-B claim that the erratic behaviour also occurs when the sun is at a low angle.
So the Blue Syk Effect is the cause. What a lot BS!

Come to think of it Audi was the first to come up with LED DRL in the A4 and Audi engineers got it right the first time as I have not see any A4 in bright sunshine with both the DRL LED lights on together with the headlights ever!

So it looks like only Mercedes-Benz failed in their design of the auto-lighting feature.

For peat sake if M-B is aware of this issue since 2009 why not simply redesign a light switch that allow the driver to turn off the headlights like all the other car manufactures are doing?
That would give the driver more control but I guess that would be too simple!

 

Interesting discussion. I read most of this page. Enough to get the point about "O" not really being "OFF". I offer the following explanation from the Operator's Manual of another Northern European make also intended for both the Canadian and USA market. Perhaps the problem lies with European implementation of the Daytime Running Light feature.

This is from the manual of my car. The 1999 S70 I sold last year used the same system.

Wayne

 

The system works fine on my '06 ML, though my '08 BMW is better.

 

Off topic, perhaps, but this whole thread illustrates the problems faced by a vehicle manufacturer who wants to sell his vehicles in many different countries, each with its own lighting and DRL regulations. I can't believe Mercedes is incapable of "getting it right" with their light sensor if BMW has apparently done so, as in my experience a host of engineers migrate between the two companies every year, taking their knowledge and experience with them. And venchka, in his post above, shows some of the difficulty: did you read stright through those Volvo lighting instructions and fully understand everything without having to re-read any of it? Not me. I actually burst out laughing when I got to the bit about the DRLs automatically turning off when the lighhts automatically turn on, and the DRLs automatically turning on when the lights automatically turn off. How much engineering time was spent developing the software and controls for that silly little dance to take place?

The world has gone mad.