1997 C230

Car running A-OK... I get a "light-out" indicator on the cockpit display > run a diagnostic and determine that my center brake light bulb is kaput.

I purchase a new bulb at the local Benz dealer [$20!!!!! for a freaking brake light bulb!!! what is it > these bulbs specced for the space shuttle??]

anyway > I install the bulb > indicator light goes off > I'm thinking all is well

But NO!!! first time I apply the brakes > indicator light is back on...

what gives???