I don't know who else might have had these problems but anyway this has been my solutions.
The front turn signal sockets on the 1998 A6 are a royal pain in the butt. I got tired of trying to work with the stock ones because they either vibrate loose or the contacts get corroded. So, I clipped them out with wire cutters, went to my auto parts store, got an American style bayonet base with leads and soldered them into place. Problem resolved.
Kinda the same thing on the front brake pad sensors. A lot of the replacement pads will have sensor wires but the plug doesn't match the Audi style female socket. You can usr push on wire terminal on the male pins, run a wire to the cars sensor wires and solder it onto them, cover with a hardening silicone and be done with that problem also. Then you can still get the feature to warn you of front brake pad wear. The EBC company pads have the sensor wires and they are some great pads to put on your Audi. They come in several styles depending on your style of driving needs.