Dash and Running Lights Out - 96 Mighty Max

Recently, when I was driving my beloved Mighty Max at night, the dashboard lights began to flicker and dim before going dark. This also made the rear running lights go dark. I realized these two items are on the same fuse.

I replaced the fuse with one of those fancy fuses that lights up when the fuse has blown. The new fuse lit up as soon as I plugged it in, which is an indication of... something?

Has anyone else had this issue? I suspect it's either a short circuit or a wire that has been rubbed bare.

Yup, sounds like a short, and a wire rubbed bare where it can touch a ground could be one cause of that.

It'll prolly be a PITA to track down, but I'd start by tracing the wires to those rear running lights, since those are somewhat more accessible/visible/exposed than the ones up in the dash. Anything else on that fuse circuit?