I need some 3rd brake light Help here

Picked up a Camper Shell on the Cheap. Fixed it up and put it on. Now we go to the 3rd Brake light. PO had a trailer attachment for the wires to the 3rd Brake light. Got a Matching plug and wires for it. Now we jump to the drivers side brake lights assembly. I know which is the Signals (Amber) and the reverse (Clear), then to the regular lights and Brake lights. I have NO help to do this so I ask what wire of the 2 going to the Brake/Regular lights do I hook up to. I sure do not want to start cutting on good wires without knowing which one is it. One is green, the other black on the very bottom light for the 3rd brake light on the shell? Anyone ever do this?

 

I have my 3rd light hooked up. Just look up on the 12 volt. Com. If I remember correctly the green is break.

 

On mine, it turned out there were 2 green wires and a black going to the brake light 1157. The black is ground, the pure green was running lights (Headlights) and the green with the red stripe was the Brake light.

This is on a 2000 Tacoma TRD SR5 Extended cab.

 

Thats exact one I got but I couldnt remember its been a while since iv done mine