Trailer Hitch 4 Pin To 7 Pin. A hitch pin is a small metal rod that keeps a ball mount shank and other trailer hitch parts from sliding out of a hitch receiver tube. There should be a common color for both the tail lights.
It gets complicated when you have trailers with more cables, and in this case, you need an adapter to make the connections. Wiring your four-pin trailer can be a challenge when you first do it, but it's a simple do-it-yourself task. Are you checking this with the trailer NOT hitched to the truck?
Cut the four-pin plug off of the trailer harness.
This could be a pretty clean looking solution.
It gets complicated when you have trailers with more cables, and in this case, you need an adapter to make the connections. If you are hauling for a long period or over a bumpy road, you can use zip ties to tie the adaptor to the trailer connector. What is the best way to do this?