Wiring 2006 Harley-Davidson for Towing a Small Trailer

Question:

Hello, I have a 2006 HD Ultra Classic MC. I bought a pull behind trailer. The trailer was wired with a standard 4pin trailer connector. The wiring harness I purchased and installed on my motorcycle didnt come with a connector, I purchased a 4 pin connector and have parcially installed. Parcially, because there is an extra wire. The 2 wires in question are for the running lights and for the brake lights. I connected these 2 wires to the one wire going ot the trailer. I am only getting the running lights and not the brake lights. I will be off work on monday and will check the bulbs on the trailer, to make sure they are double element, Is there anything else to check or do. i will most likely purchase the parts i need from e-trailer. If I need an adapter? Thank You for your help.

asked by: Chip M

Expert Reply:

What you are experiencing can be fixed very easily.

Most trailers use what we refer to as a combined lighting system. This means that the signal for the brake lamps and the turn signals are carried on the same circuit. The 4-pole connector on your trailer carries the ground connection on the white wire, the running light signal is carried on the brown wire, the right turn and brake lamp signal is carried on the green wire and the left turn/brake is carried on the yellow wire.

The problem is that your bike uses separate circuits for the turn signals and brake lamp, instead of the combined system your trailer uses. To solve the problem, you need to install a taillight converter. A taillight converter will take the right turn, left turn and brake light circuits on your bike (3 separate circuits) and combine them into 2 circuits, one carrying the right turn and brake, the other carrying the left turn and brake. Once the converter like part # 119178 is installed, the lighting system of the bike and the trailer will be compatible and everything will work as it should.

expert reply by: Mike L