Yeah, it looks like it is part of the reverse lights wiring. On stick shift trucks, that connector is either hooked up to the reverse lights sensor on the transmission or has a jumper that connects those 2 prongs.. I cant really remember how it hooks up. On automatics, the reverse lights are controlled through the Neutral Safety Switch and that particular connector is not used, or maybe that is where it has the jumper.
Anyway, it definitely has to do with your reverse lights and there are a few different ways to use that connector depending on how your truck is set up. So if your reverse lights work, then don't worry about that connector as your truck is set up right. If your reverse lights do not work, then research how to complete that connection based on what transmission your truck is equipped with.
