Serious condensation Issue with NS hadlamp

platforminc

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Hi Everyone.

Its been a while on the forums as I sold my W212 over a year ago, now I got myself a cls over the summer.
What I have noticed since last week was that the headlamp has a lot of condensation in it, this started about 3 weeks ago when the weather changed and it suddenly became colder.

The irony is that the OS headlamp is fine and doesn't have this issue. I was told that this will go away by itself after sometime. its been like this for some time now and I am not sure what to do.

Any advice please.

Ns Lamp
WhatsApp Image 2020-10-18 at 21.16.51.jpeg

OS lamp

WhatsApp Image 2020-10-18 at 21.16.51 (1).jpeg
 

mioba

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I would be inclined to take a bulb out (if posible) and get a hair dryer in there. The process might reveal a loose seal.

Make sure all the seals around the light are in place by comparing with the non-condensed unit.
 
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Moisture is getting in somehow, usually via the back when a seal is loose or open, letting moisture in, verify that the opening lid (whatever it's called) on the rear of the light is tight and firm before troubleshooting any further, also look for any cracks/holes in the front lens, if all looks ok, then try cleaning the seals around the rear of the light and make sure it's properly closed so no water can get in. If you do go the hair dryer way, make sure it's not on full heat and keep it at a distance from the light otherwise you may risk melting the lens and that'll cost a lot to replace.
 
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platforminc

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Hi All.

Sorry for the late reply, I didn't get an alert that the post has a reply.

I have checked and cant see any obvious cause of the problem. But then again my hands are big and cannot really get into tight spaces. I do not feel confident taking out the headlamp, I wouldn't even know where to start.

It appears to have got worse with the rains today, as in the moisture got really bad.

Thanks in advance.
 

Craiglxviii

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Hi All.

Sorry for the late reply, I didn't get an alert that the post has a reply.

I have checked and cant see any obvious cause of the problem. But then again my hands are big and cannot really get into tight spaces. I do not feel confident taking out the headlamp, I wouldn't even know where to start.

It appears to have got worse with the rains today, as in the moisture got really bad.

Thanks in advance.
What lamp type is it? If anything other than LED...

1. remove the back caps (allow as much air to freely move in & out of the lamp housing as possible).
2. Start the engine and put headlamps on full beam.
3. Call the Mrs for a brew, sausage roll and a good book, sit in the driver’s seat on the pretext that “the gauges need watching” and wait for an hour or so, with the car on tickover.
4. Turn engine off, replace back caps on lamp.
 
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platforminc

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What lamp type is it? If anything other than LED...

1. remove the back caps (allow as much air to freely move in & out of the lamp housing as possible).
2. Start the engine and put headlamps on full beam.
3. Call the Mrs for a brew, sausage roll and a good book, sit in the driver’s seat on the pretext that “the gauges need watching” and wait for an hour or so, with the car on tickover.
4. Turn engine off, replace back caps on lamp.

Hi.

Thanks for the reply, its LED the CLS 2016 headlamp.
 

Craiglxviii

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Hi.

Thanks for the reply, its LED the CLS 2016 headlamp.
In that case, follow those steps but with engine off, and a hairdryer pointed into the hole in the back of the lamp.
 
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platforminc

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In that case, follow those steps but with engine off, and a hairdryer pointed into the hole in the back of the lamp.
Thanks for the reply, which hole are you talking about ?
Lastly, is there a lasting solution or will I need to be doing this all the time ?
 

mioba

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OP as it appears your not overly tech savvy. I would (in your shoes) be inclined to go the dealers and show then.
The car is 2016 and they may well offer goodwill on a repair / replacement at that age.
The lasting solution is to find where moisture is getting and get it sealed. The above info is part of that process and drying the inside of the lamp.
 
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platforminc

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Thanks everyone for the reply, I will go to a mate who is tech savvy and can help me out. I have a point of confusion though, from what I read on the internet, there should be a ventilation hole on the headlamp to let moisture out.

On one hand, I am being told to use a hairdryer to let heat in through the hole, I also read on this forum that any outlets should be sealed. its making me think. What is the actual problem and what is the solution.

Is it that there is a big hole somewhere on on the lamp that needs to be closed off
OR
They have sealed the ventilation hole on the lamp thereby trapping the moisture in the lamp.

I also say this because, unknown to me the car has had some kind of repair done on the headlamp and wing, although not accident damage as its not registered, but some kind of work has been done, details I do not know.

Thanks in advance.
 

Craiglxviii

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There is a big hole for the wiring harness to go through, to access the lamp ballast and/ or change any serviceable lamps inside it.
There should be a big inspection cover on the back of the lamp that can be unclipped- it’s this that @mioba is referring to that may be improperly sealed. There’s usually a gasket.

The lamp also has breather vents, these can look like U shaped bits of pipe sticking out, or a little cylindrical affair. They contain a goretex patch which allows for gaseous exchange, basically for water vapour to be expelled from the lamp in operation.

The big problem is:
Lamps are getting bigger (lens area and volume) due to a combination of styling reasons and as becoming part of the low speed frontal energy absorption structure;
Lamps are running cooler as a) they’re LED and b) LEDs eject their thermal load backwards, not project it forwards. So there is a heatsink usually underneath the lamp (look for a finned aluminium block) rather than the halogen/ HiD bulb warming up the internal air and lens of the lamp.

Add those two issues together and you get a bigger lamp containing more air (and by definition, water vapour) with less of an ability to evaporate any liquid water that may condense (now more likely to happen due to the greater lens size and volume of water vapour).
Add to that, we are now going into winter so the air is getting cooler and damper and fogging becomes more likely...

So, the best thing to do is open the lamp up, fill it with warm dried air (hairdryer) and then ensure it’s properly sealed.
 

mioba

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Just out of interest you mention some work has been done, is the lamp in question original MB....
 

Craiglxviii

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Just out of interest you mention some work has been done, is the lamp in question original MB....
No aftermarket lamps available for these. The injection moulding tooling alone is around £3m.
 

Craiglxviii

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Is that about £1500 in Yuan?
No, they’re seriously complex tools, plus the electronics in the lamps are manufactured in Germany. Only Osram has that particular tech.
 

Craiglxviii

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In China they can reproduce anything
Not.... quite true. In fact, not.... at all true. They can reproduce most things, but as the level of tech increases, the quality of reproduction falls away quite markedly compared to the original.

These lamps represent very high levels of technology not just for what you can see, but everything else that they do in talking to the car that you can’t see. Brightness level feedback reporting over time for instance; the batch number of manufacture of the HLCU being recorded in the car’s own data loggers and matching up with MB’s batch sequencing... I could go on.
 

mioba

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copying is one thing - highly possible in CN
Maintaining quality - not interested in CN.
 

Craiglxviii

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copying is one thing - highly possible in CN
Maintaining quality - not interested in CN.
But in this case, the part wouldn’t be for sale in China... as it’s putatively fitted here. But my point wasn’t about just quality (example below):

Well known British car has door hinges costing around £60 per car set. Chinese factory takes the design and makes its own interchangeable version, car set cost £27. British design, 250k open + close cycles. Chinese design, 15k cycles...

but about function. Without OEM knowledge of the car side functional requirements the lamp must perform, the lamp itself can’t be successfully reverse engineered.

This is the sort of thing I do for a living btw.
 

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I also say this because, unknown to me the car has had some kind of repair done on the headlamp and wing, although not accident damage as its not registered, but some kind of work has been done, details I do not know.

It still may have been accident damaged and not registered (unfortunately)
 


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