I have a 2002 ML320 and the freaking brake lights are stuck on. Can anyone give me a descent description of how the eletrical system for the brakes work. I suspect the problem to be in the plunger switch at the break pedal, but I need to know what voltage outputs I should be seeing at that switch. Has anyone had a similar problem, any idea how much the switch costs. Thanks in advance for any help

 

I just had the same problem the other day. It is the Brake Light Switch located right behind the brake pedal. It's about $20 and apparently those switches are common problem with MB. It was the second time I replaced it within six months. Tell the dealer's parts department that it's the second one you're buying and you will get about another 20% off.