Third brake light not working other brake lights work on 1999 mercedes s320

SOURCE: 1999 mercedes ml320 brake lights don't work

did you check to make sure the wires going to the pedal switch are not cracked or burnt?

SOURCE: brake lights/rear turn signals

I had the same problem with my 1999 Yukon. The electric board needed to be replaced. Rust starts to build up and shorts out or blows the bulb. The dealership charged $73.60 for the part and I installed it myself (Saved $30).

SOURCE: how to reprogram 1999 mercedes s320 key remote?

just insert the key to the ignition swich and leave it for one minute, it will work for sure.
Adel

SOURCE: parking lights work third brake light works,just not back brakes?

The bulbs do not need to be replaced! The answer to this problem is believe it or not in the turn signal lever, or multi-function switch. It is extremely common on these cars, and usually mis-diagnosed. Try this before going any farther. Back the vehicle up to a wall, or have a person stand behind the car, and pull the turn signal lever slightly towards you as if you were switching between hi and low beams. I guarantee that when you put just a little pressure on the lever your brake lights will work. If you want the problem fixed, you need to have the switch (and lever arm) replaced from inside the steering column, and you need someone to remove the airbag to do this. The switch is roughly $200 from an aftermarket parts store. If you learn to drive your car and just know that when you brake you can pull back on the lever to make the lights work great, I did for a few years in mine. But I guarantee that is the answer to your problem

SOURCE: 2004 chevy 1500 brake lights not working

check fuse under hood, batery terminals coroded wire at harness if everything fails run a hot wire to rear brake line with an interuptor.
check the swich under the foot brake.
vitally