Lights, WTF is going on?

[Jimbo1959]

Aye well, they say they $hit hits the fan in three's. The third issue has made it's self apparant, bugger!

Last night I went to pick my lad up from work and I could have sworn (which I did repeatedly and vehemently after checking them out) that the dipped lights on the car had lost range of approx, 10 metres, confirmed by my lad as, upon getting in the car, he almost immediatly asked "what's wrong with the lights Dad, you can normally see further up the road than this?"

The main beam had also reduced slightly too, the range difference of which I am unable to determine as my lad says "you can damn near see into the future with the lights on this car Dad" (love it).

Normally when the lights get switched on they do a little dance up and down and then settle. When I rechecked them, after discovering the change in the range, the little dance was not happening.

I went through all the options on the lights, convenience system etc... to no avail, trying to find out what had gone wrong/changed. What I'm left with is, to be frank, dangerous after getting used to the usually stunning level of lighting provided as standard. I was not comfortable or happy to do any more than 40 mph in the dark under dipped beam conditions. I just couldn't see far enough for it to be or feel safe. Ordinarily I would have no issue or indeed thought, about travelling at 60 mph on the same road when the lights were working normally on dip.

I had thought that possibly the lights had been manually adjusted at the MOT but discounted that as they usually self adjust/level each time they are switched on.
Now I am just puzzled, as I can't find out what might be the cause of this loss in range.

When I was going through the on board computer options there was one for Factory reset and my son suggested trying that however, I am a little reluctant to start messing about without further research.

Any suggestions guys?

 

[LostKiwi]

Sounds like you have a bad height sensor. If a sensor fails the lights will default to the lowest (safe) setting.

Check for a broken link on a height sensor.

 

[EmilysDad]

My first thought is a level sensor has failed or come off ... My previous car with HIDs had a level sensor on both the front & rear suspension.

Damn .... LK beat me to it ..... at least we both agree on the possible fault.

 

[mersum1es]

intialization should be done anyway, dunno what happens if height sensor data is not available... It is common fault that light servo goes bad but both at same time... no likely...

 

[Jimbo1959]

Sounds like you have a bad height sensor. If a sensor fails the lights will default to the lowest (safe) setting.

Check for a broken link on a height sensor.

My first thought is a level sensor has failed or come off ... My previous car with HIDs had a level sensor on both the front & rear suspension.

Damn .... LK beat me to it ..... at least we both agree on the possible fault.

Thanks chaps!

At least there is a consensus in the diagnostic of the potential fault Now all I need to know is where the sensor is located, is there only one and is it something I will need special tools to check/replace?
On my last car it was located on the rear suspension, I suppose it would be too much to hope for the same on the Merc?

 

[LostKiwi]

You may have 2. One on the rear (check the anti roll bar - there's often a clamp with a linkage up to the sensor).

 

[Jimbo1959]

Due to needing decent range in the dipped lights I did a manual adjust from the default, low setting.

I've got them sitting almost exactly where they were before the sensor(s) (maybe) failed.

At the weekend I'll reset and change the sensors if the fuse is not the problem.

After Mersum1es's comment/suggestion though, I'm hoping that it is the fuse, I would imagine that would be a lot easier/cheaper to change.

Thanks everyone for your help and suggestions.

 

[Wighty]

Due to needing decent range in the dipped lights I did a manual adjust from the default, low setting.

I've got them sitting almost exactly where they were before the sensor(s) (maybe) failed.

At the weekend I'll reset and change the sensors if the fuse is not the problem.

After Mersum1es's comment/suggestion though, I'm hoping that it is the fuse, I would imagine that would be a lot easier/cheaper to change.

Thanks everyone for your help and suggestions.

Had all this with my 2009 E320cdi last year , there is a sensor and arm in the front right wheel arch on the top of the Spring . Also another arm and sensor above the rear diff (ish) . The good news is that's it's probably one of the arms rusting through and there are new improved parts from Merc which were reasonably cheap (£30?) .
If you have an icarsoft reader you can establish which end is faulty by pushing the car up and down at the front or back and see the height level changing (or not) .
The sensors themselves are expensive £100+ .
When I change winter summer tyres now I spray a load of grease of acf50 over the sensors and arms to keep them rust free .

 

[Wighty]

I have had trouble searching/finding my old threads , but if you search self levelling sensor it should come up somewhere . I took a load of pics of the old/new parts

 

[Oldspanners]

I have had trouble searching/finding my old threads , but if you search self levelling sensor it should come up somewhere . I took a load of pics of the old/new parts

A lot of old posts have gone missing since the great server c/o.
Must be stacked up on some shelf in that great digital warehouse where all things with bytes are stored with the "I wonder what this is" label.

 

[Blobcat]

A lot of old posts have gone missing since the great server c/o.
Must be stacked up on some shelf in that great digital warehouse where all things with bytes are stored with the "I wonder what this is" label.

They’re all still there, just the search function was restricted whilst we were on the old server. Hoping to get admin to renable it on the new server.

 

[Oldspanners]

They’re all still there, just the search function was restricted whilst we were on the old server. Hoping to get admin to renable it on the new server.

Thanks for the info and keeping the site running.

 

[Blobcat]

I have had trouble searching/finding my old threads , but if you search self levelling sensor it should come up somewhere . I took a load of pics of the old/new parts

Here's the thread

 

[Wighty]

Here's the thread

Nice find buddy . That's why you get the big bucks

 

[LostKiwi]

To search only this forum type this into the search window

forums.mercedesclub.org.uk:

Follow the : with whatever you want to look for.

For example to search all threads with r129 wipers type

forums.mercedesclub.org.uk: r129 wipers

into the Google search box

 

[Jimbo1959]

Had all this with my 2009 E320cdi last year , there is a sensor and arm in the front right wheel arch on the top of the Spring . Also another arm and sensor above the rear diff (ish) . The good news is that's it's probably one of the arms rusting through and there are new improved parts from Merc which were reasonably cheap (£30?) .
If you have an icarsoft reader you can establish which end is faulty by pushing the car up and down at the front or back and see the height level changing (or not) .
The sensors themselves are expensive £100+ .
When I change winter summer tyres now I spray a load of grease of acf50 over the sensors and arms to keep them rust free .

Wighty, are the prices that you are quoting for the sensors for O.E. units? £100+ each??!?!?

I got one of my colleagues at work to check the availability of the sensors and I can get a pair of febi items for less than half that price.

I also got one of my customers to give me a copy of the complete Autodata electrical system fuse and relay specs and positions to help me double check that the fuse is not the fault.

All I need is a dry day on Saturday so that I can do the work as, the car is too big for my garage I can get her in the garage but, I can't get the door opened to get out of the car if I do. Bugger!

 

[Wighty]

Wighty, are the prices that you are quoting for the sensors for O.E. units? £100+ each??!?!?

I got one of my colleagues at work to check the availability of the sensors and I can get a pair of febi items for less than half that price.

I also got one of my customers to give me a copy of the complete Autodata electrical system fuse and relay specs and positions to help me double check that the fuse is not the fault.

All I need is a dry day on Saturday so that I can do the work as, the car is too big for my garage I can get her in the garage but, I can't get the door opened to get out of the car if I do. Bugger!

I think the £100+ were MB units , yes . It was a while ago . I'll bear in kind the Febi option if I have a sensor fail though . I still think it's more likely one of the arms has gone rather than a sensor .

 

[LostKiwi]

I still think it's more likely one of the arms has gone rather than a sensor .

Ditto. The rear one in particular is prone to rust.

 

[Jimbo1959]

Thanks for all your help guys, roll on Saturday, hopefully dry Saturday.

 

[Jimbo1959]

I think the £100+ were MB units , yes . It was a while ago . I'll bear in kind the Febi option if I have a sensor fail though . I still think it's more likely one of the arms has gone rather than a sensor .

The febi ones are £33 each on various sites on the 'net, you can also get Vemo and Metzgar ones for a few pounds more.

I'm lucky in as much as I get a great staff discount at work, cost price in fact. So, the two febi units would come in at just under £44 to me.