I added a set of KC 517 Backup lights to help illuminate behind my truck. These are wired into my backup circuit, so I can clearly see behind me when in reverse. Initially, I wanted to use the trailer circuit for power, but the Ford Ranger trailer plug does not have a backup circuit in it. The only leads are taillights and left/right turn signal. I used the existing power from my bed outlet and wired the relay into my taillight backup light power lead.

To start, open your KC box and make sure everything is included and intact. KC provides all the wire and mounting parts needed for the whole install. They even provide a wire loom.	This is the backup light wires from my left taillight. The power lead is the red/black wire. This will provide signal to activate the KC relay.	I used my wire stripper to carefully remove the insulation, so I can solder my relay wire to the bare copper. I like to keep my factory wires intact, and I think soldering makes a better connection..
From under the truck, you can see the power lead going directly to the battery. This will power the backup lights when the relay is activated.	Here is the relay connected and sealed against moisture. The connections are already terminated, just follow the KC wiring guide.	The whole relay assembly fits into the cavity of the tail light. This keeps it safe and dry.
Quick test - left side mounted in bumper hole, right side uses the KC plate to mount the light further back.	I decided to use the KC brackets and mount my lights back under the truck. I used the big holes already in the bumper.	Here you see the KC bracket attached to the bumper. Nice and strong.
Don't forget to add a washer and ground wire to each bolt. The bumper makes and excellent ground point.	I flipped the frame and lens of each light, since these are really just upside down driving lights.	Here is the final assembly with the backup light in place. Much better with the frames flipped.
Now just add the wiring and protective loom. This is a splash area, so protect everything.	Final install with cabling and wires secured.	under the right fender, you can see the power tap and fuse,
The lights provide good illumination and are protected under the bumper.	This is a good project for the electrical beginner as KC provides everything.	This is the KC 517 installation manual. Please READ it carefully.