Imported and some domestic tow vehicles use international lighting in which the turn signal lights are wired separate from the brake lights. Generally an amber lens is used for turn signal lights while standard red lens are used for stop lights.
The lighting system for most American made vehicles combines the turn signals and brake lights into one wire instead of two, and has no amber lenses.
If the tow vehicle has an international system, the two separate wires for turn signals and brake lights on the tow vehicle must be combined into one for the travel trailer’s lighting system to work properly. To do this, a converter is necessary.
The converter is a circuit board built into a separate weather proof box or built into a tow vehicle plug connector.
Three or four wires coming from the tow vehicle… left and right turn, and brake wires… go into the converter and two come out. The two wires coming out are connected to the left and right turn connectors in the trailer-plug receptacle.