Why Does My Vehicle Have Separate Turn and Brake Signal Wires

Question:

I have a 7-pin plug that Im installing on my truck. Every diagram that I can find says that the brake and turn signal are in the same wire, but my truck has two separate wires for the brake and turn signal. When I put them in the same pin it connects the brake to the turn signals in my truck, therefore whenever I press the brake my turn signal turns on. How do I connect it to my trailer plug without it turning on my turn signals?

asked by: Eric

Expert Reply:

There are two types of lighting circuits for vehicles and trailers which are separate systems and combined systems. A separate system will have a separate wire for the brake and turn signals whereas a combined system will have a single wire for the brake and turn signals. The vehicle's wiring system will need to match the trailer's wiring system but if it does not then you can use a converter box like part # C56196 which will separate out the brake and turn signals or combined them together. The trailer lights would not function properly if you just attached both the brake and turn signal wires to same pin on the trailer connector.

expert reply by: Conner L