For headlights, check the dimmer switch. They're notorious for going bad. Taill light circuit doesn't go through the signal switch, but brake lights and turn signals do. Also, be sure all the fuses are good, and the contacts on the ends of the fuses aren't corroded. The voltage supply to the headlights, and the fuse block comes from a "fusible link" at the starter cable connection. Be sure it's not broken or dirty.
Jerry
