Have a 06 and the dome lights stay on all the time. I had to pull the bulbs out of all of them. They would come on during the night and run my battery dead. The lights just come on while driving down the road and won't go off either. I can hear a clicking in the dash while driving where they are coming on and off from a really or something. Sounds to me like it's coming from the instrument cluster. A little help would be appreciated. Thanks

 

Here's a diagram. You are correct, the interior lamps relay is located in the instrument cluster.

http://www.revbase.com/BBBMotor/Wd/D...dPdf?id=123709

I can't seem to find it in my diagrams, but I believe you have a vehicle security module or some other module that the door switches lead to. The door switches ground the wire from the security module, and that tells the module that the door is open. The module also sends a signal across the computer network in your truck to the computer in the instrument cluster. The computer in the instrument cluster then activates the interior lamps relay.

This all sounds complicated, and it is, but your problem most likely is just a switch in one of the doors not making good contact or a wire in one of the doors is rubbed through and grounding out, making the security module think one of the doors is open.

Do you normally get a "door ajar" message when one of the doors is open? If you do, and you do not get it when the domelights come on, then that might point to a problem in the instrument cluster itself.

 

I do get a door ajar open when the doors are opened but they go off as soon as the doors are closed. That's why I wasn't thinking it would be one of the door switches.

 

Verify again when the domelight is on with the doors shut, that the door ajar light is not on.

 

Door ajar light is not on when doors are shut. The dome light stays on constantly. Dome light comes on when I turn ignition on but won't go off till truck is turned off

 

I am going to guess there is something wrong with the cluster. Only way to make sure is to get someone who can get on the network in your truck and verify it. Of course that costs money, I am not sure if a local shop with the right scanner can check for you or if you have to go to the dealer and let them put their scan tool on it.