My wiring diagrams are for 07-08 models, changes were made.
Get the 04-05 service manual, head for the "wiring" section and see what else the fuse for the dome light feeds. In 07-08, it powers at least part of the BCM.

If you are going to try to find this without the service manual, you are going to waste a lot of time. YOu don't know the history of the car, you could have water damage in a module, chewed wires, or damage from overvoltage due to a battery cable coming loose. OR, it could be something pitifully simple.

I spend a lot of time helping people with their cars when the car suddenly develops a problem. Working on an "unknown" like yours can be WAY harder. This may take considerable effort, but you will know a LOT more about the car at the end of this.