Headlight alignment

[fredfoxuk2]

Have a 2018 C class, with standard halogen lights, not decent self levelling Xenon's. Driving into work on Tuesday, first dark morning for a while for me and thought the headlights were a "little" high. I didn't have it on main bean so just thought it was me.

For the next 80 miles I must have pissed off so many people, it was like my mail beam was on, I resorted to dialling the level switch all the way down but that didn't do much if anything. I called my dealer when they opened and managed to get it booked in just before 9am this morning (working from home today).

Picked it up a couple of hours later, to be told that the alignment was set by computer at the factory, so it must have been wrong since then - I've had the car for 18 months, I would really have noticed it before, which I told him. So somehow the alignment was reset. I had a service about 3 weeks ago and they had to do a recall which required a s/w update, which I'm now assuming also reset the headlight alignment.

Is the alignment in the car really software controlled? How would a non-merc garage sort it out?

 

[markjay]

Welcome.

The car has several dozens of ECUs, each one is updated separately, so it's difficult to say if the software update had anything to do with it, without knowing which ECU had the software update.

There was a software update for Diesel engines recently, but from memory it only affected older cars.

No idea if the headlamps alignment could have been reset during the service.... either way, if the lights are now aligned OK when the level control is on 0, and you can bring the beam up by choosing 1, 2, or 3, then everything is fine?

 

[andy27168]

I maybe confused, thought the correct headlight alignment was meant to be at "0" and you lowered the beam alignment by dialing in 1, 2, 3.

 

[markjay]

I maybe confused, thought the correct headlight alignment was meant to be at "0" and you lowered the beam alignment by dialing in 1, 2, 3.

Correct, it was a typo.

 

[Teego]

I maybe confused, thought the correct headlight alignment was meant to be at "0" and you lowered the beam alignment by dialing in 1, 2, 3.

Exactly so. Never heard of halogens being computer controlled. 10mm socket, surely. I'll be interested to know the answer.

 

[fredfoxuk2]

Welcome.

The car has several dozens of ECUs, each one is updated separately, so it's difficult to say if the software update had anything to do with it, without knowing which ECU had the software update.

There was a software update for Diesel engines recently, but from memory it only affected older cars.

No idea if the headlamps alignment could have been reset during the service.... either way, if the lights are now aligned OK when the level control is on 0, and you can bring the beam up by choosing 1, 2, or 3, then everything is fine?

Thanks to everyone for the replies.
It's a petrol, not the devils diesel The update was something to do with the ESP I think.

The lights are now back as they were after whatever the dealer did.

I find it hard to believe that the alignment on halogens is controlled by an ECU, it seems an unnecessary expense when a 10mm spanner will do I had a good look when I replaced the standard bulbs back in January last year.

 

[190]

Don't know if it's still the case but at least up to the W203 MB headlight level adjustment was done by vacuum so a leak might cause a problem although I think they fail safe to aim down. If they have replaced vacuum by ECU controlled servo motors then they have replaced a very simple arrangement that worked perfectly well for the last 40 years or more.

 

[fredfoxuk2]

I have a dashcam, normally they unplug it when the car goes in so I didn't bother to look at it until now. I can see the lights going through some sort of up & down cycle by the reflection off the tool racks. Then they drive over to one of those headlight alignment unit things. After a bit of fiddling, out comes a socket!!!!!
Why oh why do they lie about what they've done

I've attached a picture, although I'm not sure that it's very clear ........
Added another picture of the other side

Also, without knowing how it happened, how do I know it won't happen again? Sigh.

 

[Teego]

For anyone who needs halogens adjusting, forget dealers. Go to an indy or good fast fit outfit that does MoTs. They'll have a beamsetter machine. Couple of twirls of a 10mm socket and job done.

 

[markjay]

I have a dashcam, normally they unplug it when the car goes in so I didn't bother to look at it until now. I can see the lights going through some sort of up & down cycle by the reflection off the tool racks. Then they drive over to one of those headlight alignment unit things. After a bit of fiddling, out comes a socket!!!!!
Why oh why do they lie about what they've done

I've attached a picture, although I'm not sure that it's very clear ........
Added another picture of the other side

Also, without knowing how it happened, how do I know it won't happen again? Sigh.

Are you saying that you have footage showing the car being driven to a headlamps adjustment bay, and yet the dealer denies ever touching the headlamps adjustment....?

 

[fredfoxuk2]

For anyone who needs halogens adjusting, forget dealers. Go to an indy or good fast fit outfit that does MoTs. They'll have a beamsetter machine. Couple of twirls of a 10mm socket and job done.

If the car hadn't been under warranty, I wouldn't have taken it to the dealer.

 

[fredfoxuk2]

Are you saying that you have footage showing the car being driven to a headlamps adjustment bay, and yet the dealer denies ever touching the headlamps adjustment....?

Yep. The service rep (or whatever they're called) told me when I collected the car that adjustment was "control by computer" and that it's set at the factory, so was probably wrong since then, which is laughable, the car was 2nd hand when I got it and I've had the car since late December 2018 (longer than I thought!), I'd have noticed in all that time if the headlight weren't aligned and I told him this. He went on to say that they'd reset the computer and it it was sorted, I mentioned that there was a recall done when it had it's service in August, and asked if that could have caused it, he couldn't answer that.

The dashcam shows the car going into the service bay, the mechanic doing the obvious flipping main beam on & off, then he spent quite a while looking at his PC, then it looks like he put a light or something over the sensor in the windscreen. The next shot you can see the lights going through some sort of up & down cycle by the reflection off the tool rack. Then a bit later over to the alignment bay.