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2009 ML350
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3 Posts
Discussion Starter #1
Hey all. My wife has a 2009 ML350 4Matic and the rear brake light warning light kept coming on. I know many of us have had this problem and I realize there are a few fixes out there on the web but I wanted to add my 2 cents and hopefully save you more than that! I changed the bulb a couple of times and realized it wasn't a bulb issue. I removed the housing and there appeared to be a compromised or burnt area on the aluminum contact surface for the bulb. It is the small dark area in the photo in the shape of a spade.. I took a small piece of aluminum foil from the kitchen and wrapped it over the area, re-installed the bulb. Good as new and free of charge. I then put a little silicone over the joint where the lamp cover seats thinking perhaps some water had seeped in causing the damage. Just a theory. Anyhow, hope it helps.
For whatever reason, when I upload the photos, they are incorrectly rotated just FYI....
 

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W163 Crash Test Driver
2008 ML350 (Me!), 2010 GLK350 (Wife), 2003 ML-350 (Deceased)
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1,571 Posts
Couldn't you just sand that burnt spot with some Emory cloth until it's shiny again? Or is it a coating that is actually missing?
 

Registered
2009 ML350
Joined
3 Posts
Discussion Starter #3
I tried that cautiously but it appeared to further damage the aluminum coating. I could have been wrong but didn't want to risk it. Plus, if you have to sand quite a bit off, it may not contact the bulb as well when seated which caused the problem in the first place.
 

W163 Crash Test Driver
2008 ML350 (Me!), 2010 GLK350 (Wife), 2003 ML-350 (Deceased)
Joined
1,571 Posts
I tried that cautiously but it appeared to further damage the aluminum coating. I could have been wrong but didn't want to risk it. Plus, if you have to sand quite a bit off, it may not contact the bulb as well when seated which caused the problem in the first place.
I think I would just sand the crap out of that spot until shiny. If it still didn't work you could always just cover it in foil. Oh wait... :D

Hey, what matters is it's fixed! Well done.
 

Premium Member
2015 ML250 Bluetec and 1987 560SL
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3,584 Posts
I did the emery cloth thing on mine and it worked fine. The housing contact appears to be solid metal, so I don't think you can damage it that way.

I also don't think it's aluminum. When I had this problem on my 2001 E320 wagon, I soldered a piece of brass foil on it where the lamp contact touched, and it took solder readily - which aluminum won't.
 

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2007 ML350, 2012 C250
Joined
34 Posts
So many people have had this problem, apparently a design issue, MB should do a recall.
 

Registered
2012 GL 450 4Matic
Joined
1,206 Posts
They did do a campaign and do have a fix. If you are under warranty or CPO the fix is free, the parts will run you about 20.00 per side and it is very easy to do yourself. I only had to do the left side in my car.
 

Registered
2009 ML350 164.186 / 272.967 / 722.9
Joined
49 Posts
Same issue, bulb was flickering. But in my case, the tab on the bulb holder was slightly corroded -- I just sanded it and pulled it up away from the plastic socket. Couldn't see any corrosion on the receiver in the car - awkward even with mirror, and contact point was under the bezel. Snugger squeeze fit after twisting in tight - works fine...great tout, thanks! Bulb was fine. Never got a code.
 
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