when I am driving my interior lights flash sometimes on my 02 A6 3.0 I noticed that the passenger rear door sign comes on the instrument display everynow and then....but not everytime the lights flash. The door is closed tightly. Where is the door switch located, and has anyone else had this problem???? Any help would be appreciated!
Thanks!

 

That door switch should be located somehow in the door jamb or inside the door with a trip sensor of some sort. Removing the door panel is very easy (it's been covered here before - the search feature will find the links to the process). You may have a switch that is faulty and needs replacement, or it may just be dirty and need a cleaning.

 

On my '00 A6 the 'Door Contact Switch' is part of the lock assembly inside the door itself.

Feel free to read my post on Central Locking: https://www.audiforums.com/m_917648/tm.htm