Hello,
I recently purchased a 2002 A4, and everything was fine for the first few months. However, recently (whenever my headlights are on) it occasionally trips the warning light and tells me that my right front turn signal, rear parking light, and one other rear light have gone out. I've pulled over to check, and the lights always actually work. On one occasion they didn't work for a few minutes, but began working again after some time. I think it might be a loose wiring harness--are these lights all connected in the same terminal to the main power? If so, does anyone know where these wires are located? It could easily be something else though, this is just speculation. Any help is appreciated, thank you.

 

Check the bulbs first. Especially the turn signal bulb on the front right. The bulb may be causing a cross short. Next most likely cause would be the bulb sockets at the supposedly failed corners.