Rewiring a Trailer Seems Intimidating, but Is Relatively Easy

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Rewiring a Trailer Seems Intimidating, but Is Relatively Easy By Lee McClellan, the Fishing Wire

		A recent column discussed fixes for common boat trailer light problems. These problems often don’t often surface until you hitch up the trailer for the first time of the season. Sometimes, just replacing light bulbs and fixing the electrical ground won’t work because the trailer’s wiring is shot. It may take a simple repair or need complete replacement. Many boat owners put off rewiring a trailer or pay someone to do it because it seems like an intimidating job. You don’t have to be an electrical engineer to do it. You just need a buddy, a rewire kit, wire strippers and black electrical tape.
First, you must determine the extent of the problem. Wiring problems can occur in a variety of ways. A small nick or cut in the wire’s insulation can lead to corrosion and a short circuit. This renders all of the trailer lights on your rig useless. If wind from towing the boat at highway speeds blows a piece of wire into a pinch point, then the wire may be cut when you make a sharp turn. Clamps that hold the wiring to the trailer can break from a rock thrown up from driving on the Interstate and cause the same pinching problem. Inspect the area around your trailer tongue for cut or frayed wires. If your trailer wiring runs along the outside of the frame, get a flashlight and inspect it. Check the wires for bare metal or damaged insulation. You can quickly patch bad spots with shrink-wrap electrical connectors. If the wiring runs inside the frame of the trailer, then you may have to rewire it. Some boat owners - once they realize how easy it is to do - rewire their trailer every few seasons. Most rewire kits cost less than $15 and those with the new wiring and lights usually cost under $30. The rewire kits with LED lights cost considerably more. Once you’re ready to start, carefully read the instructions for the rewire kit and make sure to line up the correct set of wires for each side of the boat trailer. First, cut off the electrical plug at the trailer’s tongue. The rewiring kit will include a new plug. Next, strip about 2 inches of insulation off the ends of remaining wires that go into the trailer frame. You will use the old wires to pull the new wires through the trailer’s frame. Twist the bare metal ends of the old wire to the ends of the new wire. Make sure to match the wires correctly. For example, the brown/yellow wire from your trailer must match up with the brown/yellow wire from the kit. After twisting each wire together, fold over the ends to make sure the wires do not pull apart easily. Bundle these connections together then wrap the outside of the wires tightly with black electrical tape. This helps to prevent the connections from snagging anything inside of the trailer frame. Do not skimp on black tape on these wrappings because getting the wiring hung inside a trailer is no fun. Next, go to the back of the trailer and cut the old wires that connect to the rear lights. You can wire the lights in directly, or leave 4-6 inches of the old wire hanging from each light and spice into the new wire. Also, cut any wires leading to the yellow lights along the side of the trailer. Return to the back of the boat and gently pull on the wires going into the frame. This pulls the new replacement wires through the trailer. Make sure the new wires you just attached pull through cleanly. Keep pulling until you see the black electrical tape used to make the connection from the old wires to the new wires of your rewiring kit. Unwrap the black tape and connect the new wires to the rear lights with shrink-wrap electrical connectors, or wire them in directly. Go to the other side of the trailer repeat these steps. Splice in the yellow clearance lights to the brown wire of the new wiring harness you just installed. The plastic wire splices that snap together are easy to use. Finish these by taking a pair of pliers and squeezing the metal strip in the middle of the wire splice. This ensures the splice pierces the insulation of the wire completely. For an extra measure of weather proofing, you can wrap the splice in black electrical tape. The shrink wrap wire connectors and wire splices usually come with your rewiring kit. You are done. You’ve just rewired your trailer. Look for a future column on general boat maintenance and things to watch for in your first few trips of the year. --Lee McClellan