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2009 C300 3rd Brake Light issue

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Old Oct 11, 2016 | 08:59 PM
  #1  
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2009 C300
2009 C300 3rd Brake Light issue

Hello all. I've been lurking for a while but this is my first post.

I have a 2009 C300 that I've owned for a few years. Always serviced, never abused and have about 45k miles on it.

About 6 months ago, I noticed the warning on the console display regarding the 3rd Brake Lamp (LED strip). It comes on after the brakes have been pressed for a few seconds. It used to be intermittent but now it's guaranteed to come on every time. One thing I did notice though is that the warning takes longer to come on in cold weather and the light actually works for a while. Could be coincidental but I'm not too sure.

I've checked the SAM fuses which appear fine. MB Service have told me it could be the SAM itself but won't know for sure until they install and program a new one.

I don't know what to do . Any thoughts or help resolving this would be greatly appreciated.

PS. I have read all the threads I can find on this issue without resolution.

Thanks

Sam.
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Old Oct 16, 2016 | 02:51 PM
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2009 C300
BUMP

No one? OK. Does anyone have a schematic of the wiring between the 3rd brake light and SAM?

Thanks
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Old Oct 16, 2016 | 08:02 PM
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2010 C300 4MATIC........ 2011 C63 AMG.............. 2015 CLS400 4MATIC.....
I have no idea but free bump, sorry...

Maybe Funkwagen can help.
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Old Aug 4, 2018 | 09:06 PM
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'04 C230 Kompressor Sedan
Sorry to revive an old thread...
My 2009 C63 just started doing this as well. I got home this evening and put my phone behind the car and recorded video of me hitting the brake pedal... 3rd brake light comes on and at full brightness. Has anyone found a solution to this? I’d hate to throw a rear SAM at the car if it’s just something simple like a relay or loose wire. The warning in the dash is annoying.
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