[VetteVet]

Well if you have a short to ground in the circuit board you would certainly pop the PNL LTS fuse when you turned on the headlights. The pnl lts fuse for the dash lights gets its power from the orange wire on the headlight switch after it goes through the rheostat (dimmer) in the switch, via a green wire back to the fuse panel.

When a harness comes with a new fuse panel where different fuses may split circuits, it becomes harder to isolate exactly which fuses are fusing which circuits. it makes it much harder for anyone (me) without hands on, to isolate the short. I guess what I'm saying is that your courtesy dome fuse must be fusing the dash lights, from your details, and I don't remember reading about a problem in the circuit board. That would have been a big clue but it still wouldn't explain why the Pnl Lts fuse wasn't blowing first, unless like I said, maybe they don't use it and are using the Courtesy lights fuse.