# Check fuses (Info at the cover of the fuse box) or just replace the broken one ;-)
# Check the door sensor if it recognizes door(s) state (open/closed). maybe disassembly is nessesary
# Check button and interior lights by measure powersuply if car is started or key is in pre-ignition position
# If VCDS diag system is available. You can check for erros in one of the control units
additional infos, schematics, exploding drawnigs can be gained via erWin of AUDI - erwin.audi.com