Interior disco

[Cody Forbes]

Patient is my '98 A8q.

When the right rear door is open the interior lights flash. Not fast, they just fade in like normal, then imediately fade out like they normally would when the door is closed, and continues this cycle as long as the door is open. On all other doors the lights act normal - open the door and they fade on and stay on, close the door and they fade out. I thought it might be related to the child safety door handle lock, but switching that off didn't make the slow-disco stop.

Any ideas? 

-Cody Forbes