I just got a 68 with tail light back up lights in one unit. The wiring is all new as are the light fixtures. There are no sockets for the b/u lights. In the trunk wire harness there is a green wire exposed on the d/s and a black wire exposed on the p/s. Are these for the back up lights? Is the green + and the black - and do I make a little harness across for both or is each side + and a seperate color with the bulb socket grounding to the light fixture?