1999 e430 brakelight
 

HELP - HELP - HELP
After replacing the burned out (tail light filament) two-filament bulb from the passenger side tail light assembly of my 1999 e430 I was hoping to see both the brake light as well as the tail light working. The tail light part of the new bulb is now working but the brake light does not. The wiring harnessand the metal plate on which the bulb holders are installed look okay. How can I find and check for the feeder wire in the harness that is meant for the brake light filament of the bulb? Or, can something else be wrong?
Any help would be most apprecaited.