r129 sl500 xenon headlight problem

[wub]

I drove my 1998 r129 with Xenon headlights, for the first time at night the other day. I was totally shocked at how terrible the headlights were, the worst i have ever experienced, even in my old 1970's mini, dangerous to say the least. There is virtually no main beam at all, i could not see if there is a truck or a wall 20 meters ahead of me, on full beam and i'm not exaggerating.

So i thought the xenon optional extra was going to be a super bright, night driving experience. I have checked and i do have the xenons, ie the little round lens in the headlight and the xenon bulbs. The dipped beam seems very bright, with a very sharp cut off point. but the main beams are like trying to drive with 2 candles out front, 2 very dim orangy glows in a sea of darkness.

So i assumed the bulbs must be at fault. I have replaced the xenon with OSRAM Xenarc Classic Xenon D2S's, but was surprised to realize that the xenons are the dipped beam bulbs? And no change from what i had. So i then replaced the main beam bulbs, with Osram H1 supers's, same as what came out. But still no change, the main beam is still like dim orange glows.

After much googling, i am confused to say the least, are these Xenon headlight option good or bad? even if bad, they must be at least good enough to drive by. So that means having replaced all bulbs, i must have another problem.

Has anyone else had this problem or any idea what it could be? I cant find anything online to answer this.

 

[Botus]

usually the dip beam xenon is the same continuously illuminated "arc" on high beam.... some car's may also get additional high beam bulbs come on as well

to achieve the difference between xenon dip to main beam illumination, a metal plate flips inside the light unit (hence the term bi xenon), the failure mode you say sounds odd, as the metal plate is only to cut back to dip, and stays out of the way for high beam. So the xenon arc should remain lit and strong and the amount of light let out is the only change

if you have additional halogen main beam lights... yet it all goes wrong everywhere that sounds more like a wiring issue than the bulbs (which maybe why u have had little success having swapped it all out... )

if they ALL look OK but the light isn't hitting the road, this could well be the level sensing mechanism has gone wrong. Quite a common fault. By law in the EU market we mandated (due to the brightness of xenon's) that a self leveling system would be in place and operational. But if the suspension link rods are seized (common on Mercedes) and or the linkage fell off inside the light unit (Vauxhall Omega default failure mode). The illumination might be staring at the floor instead of down the road. Usually you should see xenon's nod when first turned on as the lamp unit goes through its self test sequence and settles to the correct level

 

[wub]

Ahh that's starting to make sense now. So do you know where this leveling mechanism sensor is, as mine has had the ADS hydrolic supension removed at some point before me, and replaced with standard springs and shocks (which the seller never told me!) so there is already those sensors on the back and the front that are, i thought, not being used anymore. but maybe they are required by the xenon headlamps to fuction?

 

[bigasotonuk]

Hi
The leveling sensors on this era MB are generally fitted on the drivers side front and rear suspension.

 

[wub]

I found them, on the drivers side as you say and on inspection, both front and rear brackets these are mounted on are rotten and broken in half. so time to look for some! Thanks

 

[Botus]

they normally seize and then snap off - you shouldn't need the sensors just the link road and associated brackets - don't know if it needs both ends working for the lights - you could try and move to where you think and see if the lights respond. Each sensor linkage is about £30

remember where a vehicle has inferior suspension it might go up and down if you touch the level sensors - and thus could kill you. Real springs FTW...

 

[bigasotonuk]

Hi,
When you get the new link rods, if they are adjustable, adjust them to the same length as the broken ones were and all being well the headlights will be at the correct height without any need to re-calibrate the sensors to the headlight leveling motors (control the headlight alignment).

 

[LostKiwi]

I suspect it will make little difference.
9gifh beam should be bright too and if the aim is wrong they'll just point at the ground or sky.
The links were probably part of the ADS system (and possibly why it was removed). ADS equipped cars don't need self leveling as the ADS does it.
High beam is a separate bulb in the same housing. You need to measure the voltage on the halogen high beam bulb. If it's not at least 12v it will be like a candle. Try putting 12v direct to the bulb to check brightness.
Park in front if a wall to check alignment at the same time.

 

[HankStarr]

Hi....I had the very same issue went to the seller who changed the xenon bulb yet didn't work. After around 4 hours of attempting they reached the resolution that the balance had gone down and I required a totally different light get together fitted at £1,063. Criticizes, I discovered one at a neighborhood breakers and threw a tantrum it for me who has a body shop, (would suggest that) absolute expense £200.

 

[wub]

Ok lots to try, thanks.