Each of these trailer 4-pin connectors comes with unique wiring diagrams ... such as their boat trailer light connector's copper core. This harness's internal structure is covered in anti-UV ...

Simply unplug the connector to the rear lights on your truck, plug in the trailer harness between the male and female ends, and you're ready. But wiring ... those schematic diagrams that have ...

No power at all to the trailer connector would mean a major break at the connector or the wiring harness. The turn signal/brake, parking, and backup light terminals at the connector receive power ...