MBRedux

Well, many here are having headlight issues… such as water and moisture getting into their headlight assembles causing condensation on the lenses etc. This condition, if left unchecked, will eventually cause the lenses to prematurely cloud up, electrical connections to rot, etc…. a rather expensive proposition.

Here’s a simple check you can do at home. It’s very easy. The only tools necessary is a flashlight and a small mirror.

I do have a simple request to all those who are actually having this condensation issue. Could you please post the build date listed on each headlight along with the part numbers on this thread? It would help MB and others with the same problem if a defective batch did make it into production.

Thanks
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Open the hood and locate the top cover behind each headlight.



Now look for this tab....



Pull it forward toward the front of the car and lift up. The entire cover will slide up and off. Set it down somehwere safe.



This will expose the entire assembly. Notice that the headlight is composed of two sections, the black rear section and the clear lens front section. (Take note on how well these two sections are glued together.) On top of the black section will be a production sticker with the build date and part number. Please remember to post this date and part number if you are having condensation issues.



Before we go any futher, check all bulb sockets to make sure they are fully secured and tight. I have pointed out where these twist sockets are located along the top. (Parking lights)




Now depending on the country you live in, there are a few *dead* sockets not in use. Some of these are sealed up, others are plugged-up. You must check these plugs to see if they are fully seated in the sockets, otherwise they will let water in. You'll need a mirror and an flashlight for this.






Now take a close look at the gap along the two sections of the Headlight. It should be very small and tight all along the way between these two sections.



Follow this gap/seal down here with a flashlight. Mine opens up about half way (I marked the opening with arrows on the pix) and could be a potential area for water to get in.



This is where water could get in.



After you're finished, simply slide the rear plastic cover back into position and push down to snap in place.

Please take a look at your GLK if you can, even if it's not an issue for you... then post your findings here so that others with the problem can compare.

Thanks and good luck.

Kamen

Excellent thread!

mr.mbenz

MBRedux, you should be working for MB.
Fantastic D-I-Y guide.

Thanks for the info.

Kamen

I checked out my car tonight before I went to the gym. Everything seems fine.

I have the exact same gap you do MBRed, in the same place, same tiny little gap between the plastics.

MBRedux

Kamen, we need your build dates and part numbers since you are one who actually has a problem. Thanks.

Kamen

Ah crap forgot that. Guess I'll have another look see tonight.

Funny how the gap in the lighting is identical to yours though, or maybe they are all molded like that. I read in the service letter that gaps were left on purpose for ventilation.

MBRedux

That's right, but they are not usually along the seal. Instead they are along the bottom or rear along with a water trap preventing moisture from entering....

That gap may be normal... seems odd though.

RedRover

Does seem odd. Hard to believe it's normal. Good job. Great pix. But then...that's what you do, right?

Taxidermist

Guys,
What was the outcome of this? I just picked up my GLK this week and noticed the condensation. Build date was December/09. Is MB saying this is normal or is it a defect?

On another note, I'm just starting to mess with all the controls and commands and am finding it frustrating that I just can't turn the radio off without turning the whole command module off. How do you just turn off the radio, but leave the navi on? Sounds silly doesn't it? In the mean while, I've been muting the radio, or switching it to Aux. There's got to be another way.

Also, on the Navi, what is the voice command that simply routes you to your "my address". In my other vehicles, I just have to say "destination Home" and the navi takes me there. How is that done in the GLK Navi?

Thanks in advance.

NYCGLK

Seems that that's fixable per instructions above, that's what MB would prolly do, so why not save yourself hassle of bringing car in.

What's wrong with switching to aux or muting radio? Like in any car you select what music input you want. Just turn the volume down if don't wanna listen to the radio. Navi will still talk.

You have to store home address and then should be able to say "enter destination" and then say "home."

Taxidermist

Thanks for reply NYCGLK.
On the condensation issue, the above instructions only get you to uncover if you have a gap in the light housing. I don't think it was concluded as to wether this is normal or something that needs to be replaced.

Kamen said "Funny how the gap in the lighting is identical to yours though, or maybe they are all molded like that. I read in the service letter that gaps were left on purpose for ventilation."...Is it a fact that these gaps were left on purpose or is it BS?

mr.mbenz

when I p/u mine in December, the rep drove it from outside to inside the showroom to give me a tour of the new delivery. When I asked him about the condensation, I was informed that it was normal due to the vents.
Since this is our first MB, I am not sure if this in the design, or some defect. However,it has not affected the performance in the lighting. If a lot of condensation built up and then turned into water, then I would be worried. Hopefully, if there are enough complaints MB may fix the problem? It seems unusual for a model that has been tested in extreme heat and cold (Arctic) and no one every found this problem during their tests...

Kamen

I saw the letter from head office in Toronto and it stated the vents are normal and intended, new headlight design they have employed. Some condensation is normal and it should all burn off, if it starts to puddle or collect water then it would be a defect.

I just stopped worrying about it, I've chased it down enough and it seems to be operating as intended. I did however notice condensation in my driver side fog light after I got my chrome fog light cover replaced. I really, really hope I don't have to take the car in again.

Taxidermist

Thanks Kamen.
Guess it's a wait and see situation.

Now on to snows and rims...

dwlovell

Its only an issue if it persists. I had the condensation the day I picked the car up from the dealership and it slowly went away over the next 2-3 days. It happened to be VERY cold and rainy for the days prior to picking up the car, when I took it home, it was garage kept when it wasn not out driving. Since the initial condensation, there has been none even when driving through rain/cold. I remember the same thing happened with my 2002 Toy Highlander back in 2002 when I bought it new as well.

Taxidermist

Thanks dwlovell.
The condensation seems to go away. Just wondering if it will get to the point where it starts making the silver paint on the inside peel or prematurely burns out the bulbs, rusts exposed wires, or affects cornering lights performance.

Guess we'll just have to wait and see.

dwlovell

Please post back in a few weeks to let us know if:
- you never saw it at all again (my experience)
- you see it somewhat regularly, but it goes away shortly after your trip/day is over (ie: same day within hours)
- you see it regularly and it takes more than a few hours to clear, etc

Kamen

As I posted many times, after checking with MB slight condensation that appears and goes away is normal and is operating as intended.
If it begins to pool water then it is defective.

Have a little faith and stop asking the same question over and over or see a service advisor.

MBRedux

...... bump! Some here are still reporting issues with this. Over time it will cause the reflector and inner lens to become dull. I do have some moisture in the right headlight, not the left side (drivers side)... Only the right side (pss.side) assembly has this gap on my car, and it is the only one that fogs up! Hmmmmm?

MBNA109

Bump - MBRedux - you mentioned this was not a problem anymore, but your last post here seems to indicate open question still.



I assume KAMEN's guideline succinctly puts it best:
Slight condensation that appears and goes away is normal and is operating as intended.
If it begins to pool water then it is defective.

venchka

Stupid Question #8,569 in an endless series:

Mr. MBRedux,
Why don't you insist that M-B replace your passenger side headlight assembly under warranty? Huh??????????????

Wayne

MBRedux

Mmmmmm sure... Ok I'll update my last post from a year ago.

Update:
There is no problem. It's normal.

venchka

Fair enough. Fogging isn't exactly dripping.

Wayne

MBRedux

Actually in all honesty, I do't like the fact that moisture filled air can get into the headlight assembly anymore than you all do. I was at a car meet over the summer, and a Hella automotive specialist told me that if these HID headlights weren't well vented, they would overheat regularly thus sacrificing bulb life.... & they are expensive. He also said that we shouldn't worry about the condensation, unless it doesn't go away with use. I explained my concern with inner panel discoloration, lens fogging and corrosion. He brushed it off claiming that every OEM application they manufacture for the industry does this, that the better the ventilation, the better the headlight unit.... so go figure..

Phat_J

Hi,
I realize this is a very old thread, but I would like to be able to follow it to troubleshoot my car.
The pictures in this guide no longer load, would anyone happen to still have them?
Thanks!