Electrical System Flunked

lights. Get yourself a multimeter, a 12V test lamp and some alligator clip leads. Check up front around the rad support for the headlight grounding wire, bolted somewhere onto the body possibly near the battery. Make sure it s clean and tight. Pull the headlights. "Work" the connectors in and out several times to 'scrub" them. Check the bulkhead connector.

"The path" for headlights is:

Coming off the ammeter black main wire up under the dash is a big factory "welded splice" This feeds off to several components.......the ignition switch, the fuse panel "hot" buss, and power to ONLY the headlights (not tail or park)

That headlights power to the headlight switch should be checked pull out the switch so you can access it.

Before you do that, however, the power comes off the light switch TO the dimmer switch on the high or low beam wires, which pass through the bulkhead connector. Those two components are trouble spots. "Wiggle test" the dimmer switch and connector. Go around into the engine bay and 'wiggle test" the bulkhead connector.

There has been "books" written on troubles with the bulkhead connector. Learn to pull the sections apart, inspect, and repair. The ammeter circuit is a BIG issue.