Adaptive headlight/beam assist is intermittent?

[TeddyRuxpin]

Hi,

Sometimes I'm doing over 30-35mph and the high beams don't come on when the high beam assist is on - and it's pitch black, no other users or road signs to reflect anything.

No warning signals saying that it's down, the high beams just don't come on. Other times it works great.

I've actually had the high beams suddenly turn off while I'm actually driving and staying over 35, even with no other drivers about. They don't dip they kind of switch off. This has only happened a couple of times.

The screen isn't dirty (the wipers wipe over the camera anyway).

It's puzzling me, any ideas?

Cheers,

Ed

 

[Diesel Benz]

Wasn't the "speed limit" 50 km/h on a W212? 30 mph is not enough, 35 should be good.

Does this happen in the middle of your trip or just at the beginning?

 

[TeddyRuxpin]

Hey, I'm definitely going fast enough when it happens, I live rurally and there's national speed limit roads etc

It's intermittent, I think it usually works on the motorway (which is actually rarely when I want to use it) but less so on the rural roads when I need it the most, so I'm wondering if there's a broken sensor, something like the levelling sensor

Cheers!

 

[Diesel Benz]

The high beam assist works from a camera. You should see a cluster warning if an actuator or a sensor was broken (in a way that the car itself identifies it broken).

I was thinking about the initial camera warm-up period at low temp humid conditions but this does not appear to be the case here. At another forum a similar issue was caused by incorrect aiming of the camera. Should you have it calibrated?

 

[clk320x]

It only works at 35mph, I tested it today for you pal.

 

[esscee]

My way round that is to manually move left stalk on steering wheel and hold, in effect using the "flash" selection but manually hold it on and then release when any on-coming vehicles.

 

[TeddyRuxpin]

Hi guys,

Cheers for the replies - yeah, I know it comes on at 35 and turns off at 30, seems to work normally about 80-90% of the time and almost always on a smooth motorway, but sometimes it will not work even at 45mph or even 'switch off' while high beams are on, and the conditions have changed. I usually notice this in the countryside lanes that I'm driving in (always very dark).

What's curious is that when it 'switches off' while currently ON, it doesn't smoothly 'dip down' like it does if a car comes up in the road ahead, it just seems to switch off those high beams abruptly. It's a subtle difference but noticeable.

That's why I'm wondering if it's some sort of sensor for level or pitch that, if intermittent, renders that function disabled, and going over bumps (or something) will trip it.

Can't seem to find much info on it however, as I have no code.

Going in for a service with MB next month, I'll see if they mention any sensors being broken. My dad's W212 had that, there was a sensor was under the car mid way, on the passenger side that told the car's computer if the car was level or not. The service video they send you highlighted it. I have no idea what the impact of this is though (wasn't an MOT fail), or if his intelligent lights work on his though as he never uses it!

Cheers,

Ed

 

[HairyBreeks]

Hi Ed,

Did you get to the bottom of this as my 2010 E250 has the very same issue. Sometimes abruptly goes to dipped beam and stays there (at speeds well over 35 in clear conditions). If I restart the engine they work fine again.. until it happens again! No codes etc show up.

If you found the cause I'd be very interested to hear, as mine does this almost every trip now. I'm thinking of buying a used camera unit to see if the camera at fault, but seems odd that it works fine for a while and then something just shuts it down.

Cheers

 

[TeddyRuxpin]

Hi,

No, I haven't found the cause. However I have noticed that it does it on the same patch of road, I'd say 50% of the time and in either direction. It's definitely very dark with no other lights or cars around. I am wondering if it's because there's a slight crappy road and if it's some kind of sensor/electrical which gets disturbed over the bump. However, it could just be coincidence.

Other places like on the motorway or a higher speed country road etc, it works no problem.

When yours switches off, is it when you go over a bump or a patch of rough ground?

Cheers!

Ed

 

[HairyBreeks]

At one point I thought exactly that, as they went a few times in a row on the same stretch of uneven road. However they have shut down on smoother roads as well, so that ruled it out for mine anyway.

The only other thought Ive had is condensation.. possibly on the eye of camera, or on the windscreen directly in front on eye, causing it to shut down as it cant get proper data. I'm planning to investigate how the unit seals to the screen.

Maybe it has a screen change and a proper seal wasn't made when gluing the housing on, allowing too much warm air to get in front of the camera.. I might well be barking up the wrong tree with all that though

 

[HairyBreeks]

edit...had a screen change....

Out of interest have you tried having the camera recalibrated?

Cheers..

 

[TeddyRuxpin]

No, how do you do that?!

 

[HairyBreeks]

Theres a video on youtube for MB technicians, which suggests when the camera is installed into the screen it needs calibration (with specialist equipment) to function properly..

However if it was a calibration issue I'm fairly sure it would show on the dash as an error..

If you do ever get to the bottom of it please let me know, as it's one of the two faults that I really want to resolve. The other is the radio which keeps losing all FM reception (from a screen full of channels to nothing in areas with good reception)- no idea if it related in some way to the lights issue but also very annoying!

Cheers