4 Way Trailer Wiring. As the name implies, they use four wires to carry out the vital lighting functions. Four-way flat plugs provide connections for turn signals and taillight or side marker lights (the fourth connection is a ground wire).
It only takes a small break in a line to short out an entire circuit. The product was assembled without any issues no has worked effectively to this day. So here I have an older trailer which needed some work, along with re-wiring the lights.
This product was used to re-wire my boat trailer.
Some of the lights were out, but the light bulbs were fine.
The original wiring on my boat trailer was damaged and installed incorrectly by the previous owner. It's crucial to diagnose a trailer wiring problem early on to get you back on the road in the safest way possible. Heavy-gauge wire that can handle the biggest fifth-wheels, all the way down to wires that supply single-axle car haulers; all.