OK, dash lights are a bit of a trick. There is ONE small fuse which ONLY supplies instrument power but that fuse is AFTER the dash lamp dimmer control
The headlight switch receives TWO separate power circuits
The HEADLIGHTS get UN fused power from the "in harness splice," coming from the ammeter circuit. This wire suppplies ONLY the headlights and the switch has a breaker for this in/ on the switch
TAIL/ PARK get their power from a fuse in the panel, and this power ALSO FEEDS power to the dash dimmer control. AFTER power goes through the dimmier THEN this power goes to the small instrument fuse.
So......................
The very first thing to do is determine if you have power at the instrument fuse
Turn light switch to park/ tail, twist dimmer to left, and check power at both fuse clips
One thing you might try, is to vigorously twist the dimmer control back and forth several (8 or 10) times and see if you get any power at the fuse. While chekcing power at the fuse, slowly twist the dimmer, as they sometimes make contact in "one or two" spots.
IF you have no power there at the inst. fuse, and IF you DO have tail/ park lamps, it's time to pull out the headlight switch Very common for the dimmer control to get corroded/ rusty, the rubbing contact to break, etc.
Are you familiar with pulling the light switch? There's a release button up on the light switch frame. Unhook the battery, and pull the knob out to "lights", then wiggle the knob while pushing the release button. The entire knob and shaft will pull right out