Can any one tell me where and if its easy to get to, the switch thats in the door ?

 

Moved to the correct section

 

I have an issue with my 2006 2500 drivers side rear door. I open the door and the light comes on, but goes right off with the tapering off. The other doors come on and stay on until the door is closed. I don't see a switch on the door post is it internal?

 

It is built in to the door latch. You would need a new latch assembly.

 

You also may have a broken wire in the harness at the pass-thru area. That's probably more likely. Common problem, I've fixed mine a couple times only to have the wire break at a different point. The wire is probably just making contact at the break when the door is closed. When you open it, the light comes on, but the wire looses its contact, and the system thinks the door is closed again. That would explain why it comes on, then dims out. The door switches rarely fail. My bet is a broken wire.

 

Well, the light does not work all all from that door now, so the troubleshooting should be much easier in determining the real problem. Thanks for the direction for possible problem.