My wife's 02 A6 3.0 Quattro has the dash light for a bulb and the warning beep (obnoxious). I have looked over all of the bulbs and they all come on as they should.
Another curiousity that I have noticed... one front marker light lights up when I brake. I have never noticed this before. Should the other be lighting up too?

 

Update.... I have visiually inspected and can confirm that all brake lights work. I do still notice that my right front marker light (next to the headlight) lights up whenever I push the brake peddle? Is this normal? The left marker doesn't and the bulb is fine.

 

The markers has no business with brems litch Trace the labyrinths and know where it got mixed up.
U already have ur solution.