dead battery

Not knowing the wiring changes it is hard to advise you. Can you enumerate the functional path from source to headlights?

For example, if stock wiring, the path is from battery.......starter relay stud.........fuse link.......through the bulkhead (RED).........to the ammeter.......through the ammeter......out on BLACK.......to the factory welded splice............off to the headlight switch................through the switch and breaker...........to the dimmer switch............out the dimmer switch on high or low beam wiring.........out the bulkhead connector...........around the fend to the lights..........and finally to a ground point

Every point between............***.............. is a trouble point or connection terminal.