reverse lights not working !!

anybody had this problem before,a6 1996 2.6se estate auto. have checked bulbs,theyre ok.could it be the wires going thru to the tailgate,or a wire from the auto selector,or a wire from the gearbox itself? any help would be appreciated,a newbie audi owner..:1zhelp:

It's a switch on the side of the gearbox, and a connector. Rgeards Peter

many thanks for your help peter d,very much appreciated..