15. With the lens install complete, we moved back to the inside of the tailgate and worked on the wiring. While every vehicle will be different, this should give you a good idea of what to look for. On our Blazer, the wiring for the taillights was pulled back through the body and into the cargo area so we could work with it. We used a shop manual to get the color codes for each wire and a test light to double-check.