We cover a lot in this video! Read the chapter title list below to jump to the section you need, or follow along through the whole diag. This vehicle and trailer had an issue with reverse lights (backup lights). When going into reverse, the backup lights did not come on. When connecting the trailer connector, the reverse lights would be on all the time. We'll cover how to test a trailer connector, fuses, short circuit, blown fuse, jump a circuit, and read a wiring diagram.