Tow trailer wiring?

I need to wire up my trailer to tow behind my motorhome. The trailer is wired with three wires and a ground, turn and brake light on the same wire. The MH is wired for 4 wires and a ground. How can it be done?

[TRAPEZE]

Your local parts store will have a converter for this application. It is a flat black rectangular box with four wires going in, three coming out, with the ground being common. It will be clearly marked with the intended lights to be wired, and is easy for the “do it yourselfer”. Get the heavy-duty model, as these tend to burn out.