67 Barracuda Dash Dial lights

Either all of the bulbs in the dash are shot at the same time, OR the 'dimmer' needs replacing.......like a rheostat or resistor coil of sorts in the headlight switch.....It's possible that corrosion has just coated the contact area, but they will usually make sporadic contact at some point and your lights will 'flicker'........

Difficult to say......Check the fuses that serve the dash.....if they're OK, I'd try a new switch.