If I may, why not wire the lights like a trailer ( wiring and color code can be found anywhere )?
Buy the four wire HD harness for $10.00 and run the wires across the back of the car. Three to the left and three to the right. There are two common and two unique ( left and right side ).
If ever you have a wiring problem, you cna find information anywhere if you wire it up like trailer.
Just a suggestion.
