How to Wire My Inflatable Boat Trailer

Inflatable boat trailers must have lights to use them on public roads. Trailers for wide or heavy  boats may also need brakes or extra lights. Most small boats up to about 16 feet are less than 80 inches wide and weigh less than 2,000 pounds. If your boat or trailer is wider, you might have to add a center lamp or extra orange side lamps. Check the regulations for your state to make sure you get the required ligh

Bolt the tail lamps from the lamp kit to the rear crossbar of the trailer frame, as far apart as practical. Lamp kits usually include the bolts and nuts; if the kit doesn’t include them, use ordinary galvanized bolts. Mount the lamps low enough so the boat does not hit the lamp covers or block them from view. Bolt the orange side lamps to the side rails of the trailer, roughly halfway between the hitch and the tail lamps. Put anti-seize/anti-corrosion compound on the bolts before tightening the nuts with a wrench.

Pull the flat wiring harnesses through the trailer frame so you have green, white and brown wires at the right lamp, yellow, white and brown at the left lamp, and the 4-pin flat connector at the hitch. Pull the smaller brown and white cables included in the lamp kit through the trailer frame from the tail lamps to the corresponding side lamps. The lamp kit should include the connectors needed to join the cable from the hitch with the cables from each lamp.

Connect the wires to the lamps. If your lamps have short “pigtail” wires already installed, use a crimping tool with the butt connectors from the lamp kit to crimp these to the matching wires in the harness. Seal them with heat shrink tubing to keep water out. If there are no pigtail wires, look for a terminal block on the back of the lamp, or inside it. You may have to open the lamp cover to find the terminal block. Each lamp should have its own white ground wire. Using the trailer frame as a ground is not always reliable on boat trailers. Each lamp should also have a brown running/tail lamp wire. The left lamp should have a yellow turn/brake wire, and the right lamp should have a green turn/brake wire.

Connect the blue and white wires to the brake controller if you are using electric brakes. If you are using hydraulic surge brakes, connect the purple wire (backup lamps) to the reverse override connector so the brakes will not lock up when you drive in reverse.

Check that there is heat shrink tubing or another waterproof seal over every connection you’ve made. Secure the wiring harnesses with wire ties so they do not chafe on the sharp edges of the metal trailer frame. Hook up the trailer to the tow vehicle. With the key in the “on” position, test to make sure that the running, brake, left turn, right turn and four-way flasher lamps all work correctly.

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