Headlight Sw Operation

I don't know what the issue is here, only thinking out loud... Those of us who have installed headlight relays could have used a "switch on" power source to signal those relays. Lights left on would still drain the battery, just much slower. So originally, the wire to terminal marked B1 at headlight switch comes from a weld splice. It is or supposed to be hot at all times. A simply source change there would do it?
Anyway... I think the 68 Dart did drop the 2 front park lamps when headlights came on, and a lot of owners didn't like that. So maybe someone attempting the get those 2 to stay on with headlights went about it wrong. I suppose I would look first at the wiring behind the grille. Seems we already know the switch isn't the problem. good luck