Still 6V?
If you are ordering the lights, order the ones already fitted for what you need. You will not have to add any wires, there would be no place to add them to anyway. One of those wires is for the brake light which is the same bulb (or filament) used with turn signals. The other is for the running (park) lights. Ground is accomplished with the mounting of the housing.

The blue dot may be illegal, check with the local police. The glass lenses do not emit as much visibility as the plastic.

1953 Chevrolet 3600
Fried Green T'mater (Vern)
In the Stovebolt Gallery
Caution: Political Statement
Man who runs in front of car gets tired, man who runs behind car gets exhausted.