I bought a $20 set of round driving lights for my fiver. Wire the ground to the trailer frame and take a wire from the light positive wire up to the electrical junction box near the pinbox. Inside the pinbox, there will PROBABLY be a single wire with a wire nut on it coming from the main cable which plugs into the truck. This one will provide power to your new backup lights when you put the truck in reverse. You might possibly have to put a fuse in the truck to make it work. Start by checking that you have power to the backup light terminal on the truck plug when the truck is in reverse. If you have power there, plug in the trailer plug and check for power on that single wire with the wirenut.