68 Barracuda Instrument lights not working

The headlight switch has two power feeds into it for lighting. One direct; the other through the fuse.
The headlights are protected by an internal 15 amp circuit breaker.
The parking lights are protected by the fuse.

Why are they seperate? Either to insure if the headlights short out, the parking lamps and tail lights still will work; Or because even the original 40 Watt headlamps will draw 8 to 9 amps all by themselves. Splitting the load keeps both wires cooler and less likely to fail.