Interior lights/gauges timing problem

[Rufcar]

I have a question about my new 03 S interior lights that I cant find an answer for. When you shut down the car, pull out the key and close the door the lights stay on for approx. 30 seconds. The problem is, the door light go off but the speedo and tach lights stay on for a lengthy period. Yesterday is was over 10 minutes as I was opening and closing the doors. Finally they went out. That all said are the 2 circuits tied together or do they just work in tandem? Either way what am I chasing? A bad door switch? A sending unit? Something else? Thanks Jim F