1 - Spliced on 5-Pin Connector

Cut away 4-Pin, cut reverse wire to same length, spliced on 5-Pin connector with solder heat-shrinks. Wrapped wires with plastic conduit. 

Splice setup for this particular project:

Light Wires    Function         Plug Wires

Red                Reverse          Blue

Green            Right/Brake    Green

Yellow           Left/Brake      Yellow

White            Tail Light        Brown

Blue              Ground           White

I liked this better than splicing into the left tail/brake light harness.