Bonesxxx

Hi all,

On my wife's 2015 C300 4matic, the BRAKE light has been coming on. This is not related in any way to the parking brake which toggles the PARK light.

Dealer diagnostics point to the ESP module but they have taken apart and cleaned all the connectors AND removed and tested the ESP module which checks out fine.

They are now saying they think the issue must be in the body harness -- +/- $5,000 to repair is estimate -- and it is fresh off warranty.

Anyone have ideas on what else it could be before I decide next steps?

C300CA

I assume dealer or you have checked the most obvious thing first, the brake fluid level, and the brake switch set point?

Bonesxxx

I checked the brake fluid and it was definitely high (as in filled to the cap). I used a syringe to extract enough to get it down to the 'full' line. The light still came back about a day later but I was hopeful that was the issue.

Can you talk more about the brake switch set point? Are you referring to the parking brake? Because I think that triggers the PARK light, not the BRAKE light in the 2015 model.

C300CA

I just realized my brake switch question probably does not apply to C class; it is only a general question.
A brake switch is placed right behind the brake pedal lever. Its trigger point can be adjusted.
It's been too long since I had a brake switch problem so I don't remember the details. sorry.

C250OLI

I had this problem on a 2013 C250 and the culprit was an incorrectly set brake switch. When I let go of the brake pedal it wasn't coming into contact with the switch correctly. It was fairly easy to remove the bottom of the dash and find the switch on a 204 Mercedes. I would hope the shop tried messing with/replacing the switch before suggesting a 5K$ fix, that is if the 2015 still has the same mechanism.

Nifty911

A few times a week. I have the parking brake indicator come on when I first crank it up. To date no one has figured this one out, it was suggested I accidentally step on the parking brake pedal getting out but I don't do that. I pull the lever and it goes off - as it the brake had been engaged. I see this as a feature, because it's been that way for three years.

Bonesxxx

I think I posted this in the wrong forum. It's a 2015 which makes it a W205... hence the confusion on the parking brake issue. In her car, there is no parking brake pedal... it's all electronic.

huotalicusC200K

wen this happened to my w203
it was the other brake light bulb ...i couldn't understand it either the fog lamp remained on and lit
my dash said secondary brake light malfunction something like that do not quote me on that
so i replaced both brake light bulsb and it solved it
i think when one brake light blows the Mercedes tells the ecu or something like that to light up an emergency light in ordeR to let you know a light bulb has blown ..HENCE WHY MY REAR FOG LIGHT REMANINED LIT
thats the simplest way for me to put it...ill do some more research and get the aNSWER I HOPE THIS MAKES SOME SENSE , TRY TO REPLACE BTOH SIDE OF THE LIGHT BULBS