73 Dart No Headlights, Turn Signals, Brake Lights, or Parking Lights

Some of you are full of crap. Headlight switch in a Mopar has nothing to do with brake, signal lights. Only trail/ park and headlights. If there is something like a grounding problem at a lamp then it can lead you down a false road.

All interior power comes off the big welded splice in the black ammeter wire. This branches off and feeds headlights only power to the headlight switch, feeds the "hot" buss in the fuse panel, feeds the input to the ignition switch, and goes back out through the bulkhead to the alternator

The tail/ park lamps are not feed off headlights circuit. They come from a fuse in the panel off the hot buss

Brake and signal are both fed by fuses in the panel. Brake lamps are fed by a fuse off the hot buss, the signal lamps fed by another fuse fed by the ignition switch.

You have THREE major separate distinct circuits here.