How to Rewire a Boat Trailer

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Your boat trailer wiring is attacked by the elements every time you take it out, eventually leading to deterioration. It is also subject to damage caused by vibration, abrasion, and nicks and scrapes. Whatever the cause, damaged or nonfunctioning trailer lighting should be corrected immediately. Rewiring the trailer ensures continued safe operation and can be accomplished in less than an afternoon.

Items you will need

  • Rewiring kit with wire and connectors

  • Wire cutters

  • Wire strippers

  • Pliers

  • Wire connectors

  • Electrical tape

  • Wire ties

  • Additional 16-gauge wire

Step 1

Cut the old wires at the rear of the trailer several inches from the entrance to the light fixtures, leaving enough to connect to the new wires. If the leads to the lights are connected to the wire harness with wire nuts, unscrew them and leave the short lengths into the lights.

Step 2

Cut the wires at the front of the trailer several inches from the entrance into the trailer frame.

Step 3

Tape the ends of the wires at the trailer front to the end of the wires in the rewiring kit. Match the colors: brown goes to the two taillights, green to the right-side stop/turn, and yellow to the left stop/turn. The white wire is the ground and does not need to be taped to the other white.

Step 4

Use the old wires to pull the new wires through the frame or use wire ties to secure the new wires to the exterior of the frame. Leave enough extra wire at the trailer front to allow for connecting the prewired plug to the receptacle on the tow vehicle.

Step 5

Connect the white wire to a ground point near the front of the trailer. It must be securely connected to the metal of the trailer so it can provide a ground for the lights.

Step 6

Cut off the extra lengths of wire at the trailer rear, leaving enough to make connections to the wire leads entering the lights.

Step 7

Cut an additional length of brown wire if needed to connect to the second tail light lead.

Step 8

Strip the insulation from an inch of the wires and connect to like-colored wires using wire connectors.

Step 9

Wrap the connectors with electrical tape to provide additional security and protect the connections from moisture.