Fuse Box Help
A dead short is supposed to burn something. Once you install a fuse that wont blow the wire , etc.. begins to burn. That will lead you to the problem. Just kidding. I remember when people would wrap blown fuses in foil ( chewing gum wrapper ).
Try this ... remove the dome lamp bulb. Put a test light at the fuse box even across a blow fuse. When the test light goes off the short is gone. Saves on fuses anyway.
I'm going to guess what your problem is. The wire insulation shrinks with age and heat exposing bare wire that creates short circuits.