Brake lights don't turn on, but turn signals do

Hi All,

I read through some related issue posts from 2016. My 2001 E825 4-seater, T2, has braking light issues.

I replaced the bulbs in the brake lights, turn signals work just fine, but no response when braking.

Would I need to replace to replace the master brake switch (I believe that’s what it’s called) underneath the dashboard? I don’t believe this issue is caused by lack of movement in the brake pedal.

Thoughts and where could I buy replacement parts?


Switch is at the top of the frame that holds the pedal. Clean the crap off the plunger “rod” of switch and spray with a little bit of light penetrating oil, and work it by hand. When the plunger moves out the lights turn on iirc.

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^^ What Jrjava said ^^^
But you can also check the electrical function by jumping the two contacts and see if your brake lights activate.

The switch is super dirty so I will try to wipe clean and throw some WD40 into the mix.

I see there are two electrical contacts on top, but also two separate electrical connections to the switch directly below. Are they both brake related or only the top switch connected to the plunger?

@AssyRequired I do have a jump starter but can imagine the clamps are too large to pit down into the console and attach to each connection. How would you go about jumping it?

As always - Thanks, All!

No- Don’t use a Jump starter!!
I use the term “jump wire” as a simple wire that jumps from one terminal to the next.
A paper clip or a quarter will work, but you need an assistant or a darkened garage to see if your lights actually came on.
A set of alligator clips with a wire attached between them would be ideal.
(get the picture?).

Makes sense now - Yes.

Will attempt this evening and respond.