My 1987 240DL flunked VA safety inspection for "no brake lights". Last time I looked at my wife driving away they worked fine. Not now though! I've found power to the brake light switch and away from it when the pedal is depressed. I've studied the wiring diagram but can't figure out the path to the rear lights. (the tail lights work fine) The wire from the switch to the lights (blue with red tracer)goes to some device after which different colors wires go to the lights (blue ?). I think the "burned out bulb" warning sensor is that device, but I can't figure out where it is or looks like. I also discovered that the back-up lights are not working. All thoughts and suggestions appreciated.