Four way brake union

silly question I know you guys are talking trucks but does anyone know where the parking brake switch splices into the harness on a 1970 A body ralley dash in a Dart Swinger? I have a parking brake handle with a wire coming off the switch and no wire in sight from the harness to connect to. I have visually traced the black wire from the brake block, to the bulkhead connector then up to the dash, it splices off to the round connector to the printed circuit, then continues on to the fuse panel ( I think... I did do this visually LOL!) and there is no copper showing anywhere where the wire may have once been connected in the immediate area of the parking brake handle..