66 Bird Brake Light Question.

[66BirdMan]

Hey guys. I'm new here. Fixing up my grandma's 66 bird. The first car I ever drove, as a kid years and years ago.

Started work on the tail lights last night. Replacing bulbs, and some of the sockets were corroded pretty bad so replaced the pig tails inside and got them all working again.

My question:

I noticed, the center light, that has the reverse light in it, also had 3 dual filament bulbs, behind the red dome covers inside the housing. The back side, has 2 wires to each of them, but only the black wires run to the plug, and the other green wires, aren't connected to anything.

Those green wires, if given power, would allow the center light, to act as, not only a running light, but light up bright as a brake light as well. So when headlights and running lights are off, and brakes are applied, the entire row of lights would light up as brake lights, instead of only the side lights leaving the center light off.

Or when running lights are on, allowing the 2nd filament to turn on brighter, so again, the entire row of lights acts as a brake light, instead of just the side lights, lighting up bright as brake lights, leaving the center light dim, as a running light only.

The wires are there on the back of the housing, but the plug only has 2 wires running to it, one for center running light, and one for center reverse lights. The car isn't wired to allow the center to light up as a brake light. Even though the housing itself is wired to be able to.

We have the complete housing off the car and powered all the lights with a power probe straight to the battery. Testing all the lights. When testing them all together as one complete brake light, they all come on, but come on kind of gradually and not right away, and don't seem as bright. So we are thinking, in order to make it work, we would need to add another relay, getting power from the brake light switch.

Has anybody done this before?