Ryan Kennedy

I need some help! i built a flat bed for my truck and i am trying to wire up led tail light fixtures using the existing harness for the oriinal tail lights I need to know what the colors of the wires are for each function. wiring harness has 4 wires one harness is Black, Dark green, Light green, Brown other Harness is Black, Brown, Light Green, Yellow what does each wire do? i can not seem to find a diagram online anywhere explaining. Thanks, Ryan