I drive a 2002 A6 3.0 and I have an annoying on again off again buzzing sound that seems to be coming from the dash behind the centre two vents above the stereo. The sound stops when I use the directional signal. Some days are worse than others. it is driving me crazy. Has anyone experienced this and were you able to fix it???:

 

Well this is the wrong place to post this but i'll answer it anyway.
Its most likely the hazard switch (red triangle in dash) which also doubles as the turn signal relay. It kinda makes a wicked buzz noise when it goes bad.
If changing that doesn't fix it, then there is a short in the turn signal stalk itself. Un-plug the hazard switch as not to damage the new one, then change out the entire turn signal stalk. There is a wite up on audiworld on how to do this. The hazard switch going out by itself it much more common though.

 

^^^+1