Need help - Wiring colors for Tail lights

2007 3124 KB,

When replacing the tail light assembly on the right side (not the side with the license plate), there are only 3 wires exiting the trailer...gray, green, and yellow. I need to know which colors match up correctly with the light assembly. I am not getting any right tail light power at all no matter what combination. The other side works properly. Even tried removing the small wire connecters and wired each 2 wires together directly, still nothing.

Any help appreciated!

Carl