blindscout

Hi, so a few months ago a warning message appeared saying 'Third brake lamp' which indicated that my middle brake lamp is not working.
Even though they are LED and supposed to last many hours, I figured I was just unlucky.
Then, shortly after, the left brake light also went out!

Is it just pure luck that 2 sets of LEDs went out in a short period of time or is there another reason why they may have gone? Maybe a fuse, or some other contact? Are car washes to blame? Or maybe the fact that all brake lamps are on the boot which is sometimes slammed in order to close and that may cause it to break?

Thank you for your input.

CarFan1

What year is your vehicle? If it is a 2013 this is not the forum to bring your query.

blindscout

Yes sorry I am trying to delete it and post it in the right one, but I cannot find how?

CaliBenzDriver

1 -- This problem of two sets of lights going dark is likely traced to the painted GND screws that deliver poor contacts.

grounding return circuit

OMG painted GND nut 😳

They are all over the place, so instead of pin pointing the one serving your specific LED's circuits, you clean them all as DIY best practice.
A shop will fix one trouble at the time.

2-- It may also be poor voltage regulation of ALTernator output creating voltage spikes.

3-- Scan the car with specific attention for your Rear-SAM power Mgt module.

Your 2013 E-class is likely a W212 . Painted GND discovery courtesy of @S-Prihadi .