At my wits end with my 2017 Sclass. - constant reoccurring headlight condensation

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SclassOwner

New Member
Joined
Aug 18, 2020
Messages
18
Location
London
Car
Sclass W222
When my 2017 s350d was only 18 months old its started showing condensation in the driver side headlight only never the passenger side. I've been back to the dealership over 15 times now over the last 18 months heres a brief summary of what has happened:

* initially told its not an issue its normal.
* condensation got much worse after repeat calls to Mercedes UK they agreed to install silica gel packs which they did.
* 5 months later dipped beam fails, back to the dealership turns out the moisture destroyed the control unit inside the headlight.
* the above repeated three times in 18 months and after 3 new headlight units and silica gel packs installed Im right back again at the start moisture is appear and getting worse by the day.

Local dealership keep refitting the same headlight unit (same part number) with the gel packs, I get about 5 months moisture free before the cycle starts again.

Since last new head light was fitted the car was never washed (due to lockdown it wasnt been used much) so its not related to anything like that. Mercedes UK say I can only interact with my local dealership on this issue. I've asked them to raise the issue with Mercedes in Germany but they say they cant do that.

I'm not the only one with this issue, many others in the USA are seeing the exact same problem in the S550 model, to say Im p*ssed off is an understatement, I really wanted to keep this car but Im coming to the realization that this is not possible, as the car is now out of the 3 year manufactures warranty and I have to pay over £1800 every 5 months now for a new headlight.

Its not that i wouldnt spend money on it, Id gladly pay for the repair if it was a permanent solution.

Any advice on this would be very much appreciated, starting to look for a Lexus LS as I type this but Id much prefer to keep the sclass :(
 
Well I would have used a tube of silicone sealer on the area where the bulbs enter the headlight unit,given the price of a new one,I would gladly have to buy the rubber/plastic covers for the bulb connectors,because I would have to cut them off to change a bulb and use silicone removers to clean the area up before I used another tube and started all over again,also maybe a thin bead all around where the glass is joined to the back of the headlight just to be sure,I only had this happen on one headlight when a supposed mechanic left the rubber cover of the headlight bulb connectors.
 
Well I would have used a tube of silicone sealer on the area where the bulbs enter the headlight unit,given the price of a new one,I would gladly have to buy the rubber/plastic covers for the bulb connectors,because I would have to cut them off to change a bulb and use silicone removers to clean the area up before I used another tube and started all over again,also maybe a thin bead all around where the glass is joined to the back of the headlight just to be sure,I only had this happen on one headlight when a supposed mechanic left the rubber cover of the headlight bulb connectors.

Cheers for the reply, Im in the process this evening of attempting to remove the headlight in question. Just my luck but the driver side has zero access at the rear to remove the ballast, so i need to remove the front bumper which I have almost off now.
 
Worth checking with one of the several independents (where in London are you?) as they may have a solution that a replace the part under warranty Main Dealer may not have the experience on?
 
Worth checking with one of the several independents (where in London are you?) as they may have a solution that a replace the part under warranty Main Dealer may not have the experience on?
I've spent hours researching it online the only possible solution was a filter cap like this installed on the two existing vent holes in the headlight assembly:


Thanks for the suggestion ill call around some of the local garages, but its truly shocking mercedes dont recognize this as major design flaw, especially in their flagship model :(
 
Wayne Gates is a London based MB specialist
The Mercedes indi's will know more / have seen more than mixed badge & generalist garages

And, as daft as it sounds, try a crash repair body shop as they also fix / solve such problems

Good luck
 
Wayne Gates is a London based MB specialist
The Mercedes indi's will know more / have seen more than mixed badge & generalist garages

And, as daft as it sounds, try a crash repair body shop as they also fix / solve such problems

Good luck
Thanks for that i really appreciate it, ill give wayne a shout in the morning.
 
Cheers for the helps guys, I rang around a few of the suggestions above and more however none really have encountered this issue.

All agree its an unusual one, I know condensation can be expected in most modern cars due to lack of heat from the LED lights. Most manufactures say it should burn off in a day or so, but in my case it get progressively worse over time until it destroys the internal electronics of the control units.

Seems theres no end in sight for this issue

:(:mad::wallbash::wallbash::wallbash:
 
I was just about to type the above. This is a recurring issue with the same faulty part which should be under warranty from when it was installed, not the purchase date of the car. Perhaps you can get a new headlight every few month in perpetuity ;)
 
As this was raised at 18 months surely it’s a warranty issue with MB ?

+1
Seems they are trying to wash their hands with it. The issue isn't new, it has been present well within the warranty period and hasn't been resolved. Being a top of their range vehicle, I don't see why you should have to find a way to resolve this at your cost. Sounds like a bad design.
 
Cheers for the helps guys, I rang around a few of the suggestions above and more however none really have encountered this issue.

All agree its an unusual one, I know condensation can be expected in most modern cars due to lack of heat from the LED lights. Most manufactures say it should burn off in a day or so, but in my case it get progressively worse over time until it destroys the internal electronics of the control units.

Seems theres no end in sight for this issue

:(:mad::wallbash::wallbash::wallbash:


LED headlights do give off a large amount of heat FYI
 
My S500L had condensation on one side as the car had sat around a lot at a main dealer before I bought it but the condensation gradually cleared by itself.

It lives in my garage overnight and normally would be in an open office car park during the day.

I did read quite a few examples of it happening though but it is supposed to resolve itself.
 
Thanks for taking the time to reply here lads.

As ye correctly pointed out its been an issue since the car was 18 months old and any repairs which have been made only last 6 month, then the original issue returns.

I've been recording the sequence of events from the start with photos, I've created a blog site to share with MB... heres the link Mercedes Benz SClass W222 - Headlight Moisture Damage

I've even tried to contact Mercedes Sindelfingen in Germany where the sclass is manufactured but they have just referred me back to MB UK, just this week they told me to attempt one more repair with my MB dealership and if this doesnt work open a case with the Motor Ombudsman, not a road I really want to go down :(

Think ill try again with them hopefully they can resolve it, to be fair the dealership they haven been great to deal with. The issue lies more with Mercedes manufacturing not willing to accept there is a design flaw in the design of the headlight assembly.

Initially I had the issue in both headlights, gel packs were installed in both headlight in March 2019. Since then moisture is only appearing in the driver side so I dont believe its due to environmental issues, or washing otherwise the passenger side would be fogging also.
 
The Ombudsman could be your best bet. Will all the information you have, they should intervene and force Mercedes to put it right one way or the other. MB UK are washing their hands with it and refusing to contact MB Germany. That leaves you with a dealership that will now charge you as it is out of warranty although any new parts usually have 2 year's warranty and so they should be able to put a warranty claim for a defective headlamp.
 
Silica gel is just an almighty bodge and I’m surprised they did that. Improving sealing or drainage would make sense, not gel packs.

It’s a shame they can’t fit lights from another S model. Mine don’t rot away every 6 months and the car sits outside.
 
Isn't Silica Gel moisture adsorbent?

I so, then what the dealer should be replacing every 6 months is the old Silica Gel packs with new ones... not the entire headlamp.
 
I also wonder if there is something else going on with your car in particular as even at its worst, the condensation has never been like that on mine.

How often and for how long do you use your car?

I used it a few times a week on short trips 35 miles or that, then once a month 200 mile trip, ive done 18k miles in the last 22 months.

I cant understand how its only the driver side which is showing the reoccurring fault
 

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