Adaptive main beam stopped working

[tommymba45]

Hi, my adaptive main beam has stopped coming on, it worked at the beginning of the year when it was dark in the mornings and early evenings but now its not coming on. I have the stalk pushed forward with the A on the instrument cluster showing and no warning lights on the dash to tell me there is a fault. Has anyone else had this or have any suggestions on what could be causing it to not come on? Also my main beam work manually so its not a bulb issue.

 

[ToeKnee]

Just a thought, but mine don't work below a certain speed, are you going fast enough to have them "activated"?

 

[tommymba45]

Yes, I have gone plenty fast enough, its very strange

 

[ALFAitalia]

Mine is very sensitive to light levels, background lighting, light from other cars, reflections from road signs etc.......but I'm sure you will have taken that into account if you have had it for a while.

 

[tommymba45]

Yes i drive through dark lanes every morning where i am going plenty fast enough and no lighting etc so the high beam should come on like it did at the beginning of the year.

 

[ChrisPDuck]

I've had my car since August, and with the shortening daylight Saturday was the first time I've driven it in the dark, so I'm only now getting used to this feature. Have you perhaps disconnected the battery since it was working at the start of the year? Have you tried toggling the feature off and back on in the settings? Is the area of the windscreen in front of the sensor clean? Have you had a new windscreen fitted recently?

 

[tommymba45]

I've had my car since August, and with the shortening daylight Saturday was the first time I've driven it in the dark, so I'm only now getting used to this feature. Have you perhaps disconnected the battery since it was working at the start of the year? Have you tried toggling the feature off and back on in the settings? Is the area of the windscreen in front of the sensor clean? Have you had a new windscreen fitted recently?

i haven't disconnected the battery at all, I have put the stalk forward and back to see if it works but still no, the windscreen is always clean as i get the car cleaned regularly and also no new windscreen.

 

[ChrisPDuck]

There's a separate setting in my dash, under 'Settings' -> 'Light' to activate this feature so that it comes on when the stalk is in the forward position. With the feature deactivated the stalk works as a manual main beam. Have you tried deactivating the feature in the settings and then reactivating it?

 

[tommymba45]

There's a separate setting in my dash, under 'Settings' -> 'Light' to activate this feature so that it comes on when the stalk is in the forward position. With the feature deactivated the stalk works as a manual main beam. Have you tried deactivating the feature in the settings and then reactivating it?

I have looked through my settings and can only find how to activate or deactivate the adaptive main beam. Thank you for your suggestion though!

 

[ChrisPDuck]

I have looked through my settings and can only find how to activate or deactivate the adaptive main beam. Thank you for your suggestion though!

That's the setting I was referring to. Have you tried toggling it off and back on again, maybe in combination with turning it off and on at the stalk? So: turn it off in the settings, turn the lights on manually, operate the main beam with the stalk, set the lights back to Automatic, then re-enable the feature in the settings? I'm not claiming this will work, just offering it as a suggestion. Sometimes turning things off and back on again can clear a problem (e.g. folding mirrors sometimes need to go through a manual cycle after the battery has been disconnected).

 

[keith of kent]

I ahd this on my E class when the auxilary battery was on its way out. The hold function on the footbrake stopped working and the green light for stop start also stopped working.
No idea if your A class has an aux battery. Scan the QR sticker on the B post with a QR app on your phone. It will show the location of batterys

 

[markjay]

No idea if your A class has an aux battery. Scan the QR sticker on the B post with a QR app on your phone. It will show the location of batterys

It might not show the locations of the auxiliary battery if it's a capacitor rather than Lead-acid? Hopefully, someone with a capacitor can check the QR code on their car and confirm?

 

[tommymba45]

That's the setting I was referring to. Have you tried toggling it off and back on again, maybe in combination with turning it off and on at the stalk? So: turn it off in the settings, turn the lights on manually, operate the main beam with the stalk, set the lights back to Automatic, then re-enable the feature in the settings? I'm not claiming this will work, just offering it as a suggestion. Sometimes turning things off and back on again can clear a problem (e.g. folding mirrors sometimes need to go through a manual cycle after the battery has been disconnected).

Yes i have tried all of these things but cannot get them to work. Thank you

 

[flying haggis]

In my case travelling along rural lanes I find that I can never go fast enough in the dark to bring on the main beam and if Ido manage to go fast enough it then switches off when I slow so to me it's a waste of time having activated. There should be a facility in the settings to enable it at what speed you want. If I leave my house in the dark I need full beam from start.

 

[ToeKnee]

In my case travelling along rural lanes I find that I can never go fast enough in the dark to bring on the main beam and if Ido manage to go fast enough it then switches off when I slow so to me it's a waste of time having activated. There should be a facility in the settings to enable it at what speed you want. If I leave my house in the dark I need full beam from start.

If you turn your lights from "auto" to normal then the main beam works as normal at any speed too.

 

[flying haggis]

Yes I know but why give us the option of an auto system that doesn't work at slow speeds?

 

[ToeKnee]

Yes I know but why give us the option of an auto system that doesn't work at slow speeds?

No idea but maybe it's so it's not on main beam in built up areas??

 

[ChrisPDuck]

No idea but maybe it's so it's not on main beam in built up areas??

It has a light sensor to determine if main beam is required, which would account for that requirement though. I agree with Haggis - if it's dark and I'm moving, why not turn on the main beam regardless of speed?

 

[ALFAitalia]

I've not noticed my ones not working at any speed....no matter how low. Maybe another thing to sort....or not!

 

[BTB 500]

There are several different flavours of adaptive main beam - our 2019 W205 has "Adaptive Highbeam Assist Plus", and that activates partial or full main beam above 15 mph (25 kph) when there's no street lighting. Ultra Range Highbeam becomes active at 25 mph (40 kph).