Wiring For Backup Lights On Toy Hauler

Update. I removed the 7 pin connector and pigtail from the truck. Peeled back all the electrical tape and inspected the connections. I found that the black w/green wire was never connected. It was taped back against the wire harness. I don't know why they would go through that when they just could have connected the wire. The truck has the towing pkg and was wired from the factory. I connected the black w/green stripe wire to the center pin on the 7 pin connector and pluged it back into the trucks harness. Tested for reverse or backup light and it works.. Now, adding a relay and running wire to the back of the trailer and connecting to ramp lights will be the next step.

Thanks for all the feed back...