I've noticed an odd issue recently with the airbag light displaying on my dashboard. The airbag light comes on only if someone is sitting in the rear passenger seat. It does it intermittenly as if they move just right or perhaps pull on the seatbelt. Any thoughts? Is this some kind of safety precaution they have built-in that I'm unaware? My car is an 04 A6 2.7T.

 

I know when I removed my back seat there was an airbag plug going into it I beleive they have a sensor in there to detect when someone is sitting in the seat so the system knows when and what airbags to deploy in an accident.

You might want to pull out the backseat bottom cushion and look at the airbag wires and connection. Also if you have vagcom it will show a code to tell you what the problem is.

 

I know that the 2005+ A6s have chronic problems with the airbag sensor in the rear seat. I don't know if the C5 had the same problem.