Lights OUT!

[65'RustBucket]

Hey all! The Rusty's been runnin' good, but the dash lights and dome lights have been intermittently working and the running lights in the tail are OUT.

The strange thing is that the dome and panel lights work when I leave em' for a while (a couple minutes everything off), but as soon as I pull the knob all the way out and turn on everything (headlights, dash lights, dome light) the dash and dome lights flicker and die.

I was wondering where I should start? I've already changed the headlight switch. I don't see any alarming looking wiring underneath (ratty, melty, chewed up looking wires). Fuse box then? Or a bad ground? I was wondering if anyone else has come across this problem and what their fix was so I can get an idea of where to begin the search. Plus wiring sucks really bad so anything to alleviate some of the headache would be very helpful.
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-Side-
Rusty runs pretty good! Could use a valve job, but all in all runs fine. Put those FJ cruiser steelies on her and boy do the big tires help for easier freeway cruising speeds. Still kinda slow top speed (guessing I have a really short gear in the rear) but still better. Best of all, however, is they really fill out the wheel wells while still maintaining the steelie look! I would definitely recommend purchasing a set if you get the chance!