That should work. Are you not mounting them on the bumper?
I'm still a bit confused. Most of the "fog" lights I've installed only have one wire. The grounding is handled by the mount itself.
"But it does me no injury for my neighbour to say there are twenty gods, or no god. It neither picks my pocket nor breaks my leg." - Thomas Jefferson, Notes on the State of Virginia, 1782
Arguing with a truck driver is like wrestling with a pig in mud, eventually you realize the pig enjoys it.