Trailer wiring generally doesn't meet high standards. Lower quality means a significant failure rate. Boat trailer wiring needs to survive in extreme conditions-such as submerged in salt water. Thankfully, there are solutions available. New advancements in light technology offer greater water resistance. Combine this with a secure, water-tight seal at all the connections, and a light system that will reliably work in wet conditions is possible.
Install LED trailer lights. The wiring inside of these lights is fully protected. They are sealed units, waterproof, and have a very long life. Instead of using an incandescent bulb, they have light-emitting diodes. They also have a universal, water-tight, 3-wire connection that easily splices to the trailer wiring harness.
Install the trailer harness in PVC pipe. Run the wire in PVC pipe rated for electrical use. This pipe is resistant to ultra-violet radiation, heat and cold, and is inexpensive.
Splice all connections with crimp connectors and secure them in the PVC pipe. Do not mount the pipe to the trailer until the ends have been sealed. Make sure the pipe routing design has the pipe openings pointing downward. This will help keep moisture out.
Seal the ends of the pipe with urethane foam. There are products on the market that will make a permanent, water-tight seal. Some of them are U.S. Coast Guard-approved for marine use. Aerosol cans are available at home centers, and come equipped with a spray nozzle that will reach into the opening. Fill the opening with expanding foam.
Mount the pipe to the trailer with clamps. Use clamps that are designed to fit the body of the pipe and will properly secure it. Drill holes and screw the clamps to the trailer frame. Wrap the lead off connections in electrical tape. Cinch the ends of the tape with small tie-straps to prevent the tape from unraveling.
