Check the Ballast, my 2012 A6, has 2 on each light, one at the back and one underneath the headlights, my headlight is letting in water so that’s a good reason, why it stopped working, can’t seem to find where water is getting in, I’ve attached pics of Ballasts one has 2 x connections at the back and the other one has 1 x connection, I’ve managed to get one light working got 2 x new ballasts, mind you it’s now showing Headlight Range Defective Fault, and the light is poor, waiting on 2 x more Ballasts,