I rewired the entire trailer running lighting system. It came with the snap on connectors. I changed everything to Sta-Kon brand crimp connectors and used the Sta-Kon crimp pliers. Inside each crimp I added a bit if dielectric grease and then covered it all with waterproof heat-shrink tubing.
Where the wires from the light came thru the wall frame I first added a piece of heat shrink over the wire. Then I sealed the drilled hole with silicon while positioning the wire in the center of the hole for maximum abrasion protection..
All trailer running lights wiring is run inside the trailer (not under the frame) in a space on the top of the walls that will be accessible with a removable cove molding.
Where the wiring comes from the hitch there will be a fuse block in the front of the trailer with a fuse on each of the incoming wires. This way if something does short out on the trailer signal, tail lamps etc. The fuse in the trailer will blow and NOT take out the lights on the tow vehicle.
