How to fix a trailer plug
If you've ever had to tow a trailer, then you probably know how frustrating it is to finally get your vehicle in position to hook up, and realize that none of the lights work, or walk around behind your vehicle to find that you've just smashed your trailer plug. I tow trailers on a regular basis and can sympathize with anyone who's been through that. Over the years I've had to replace or rewire several trailer plugs, due to damage and corrosion. Here's an overview of how to go about fixing a damaged four wire, six wire or seven wire plug.
4 wire plug
The standard four wire plugs are definitely the easiest to repair.
White Wire- Attach to good ground (frame)
Yellow Wire- Attach to left turn signal
Green Wire- Attach to right turn signal
Brown Wire- Attach to taillight
Plug in the trailer and check for proper operation. Step on the brake pedal to check the brake lights, turn on headlights to check tail/ parking lights and operate turn signals to check right/ left turn.
Round 2 inch, 7 wire plug
This plug allows additional pin for auxiliary 12 volt power or backup lights. Uses: heavy duty landscaping/ dump trailer, car trailer, boat trailers, horse trailer, travel trailer or construction trailer.
6 wire rectangle
Green Wire-Right turn signal
Yellow Wire- Left turn signal
Brown Wire- Taillight
White Wire- Ground
The Red and Blue wire can be used for brake control or auxiliary.
Use on a small motorcycle trailer, snowmobile trailer or utility trailer.
Round 1 1/4 inch, 6 wire plug
This metal connector allows 1 or 2 additional wiring and lighting functions such as back up lights, auxiliary 12v power or electric brakes.
Uses: horse trailer, travel trailers, landscaping trailer or car trailer.
Note: The black (sometimes red) 12v and blue electric brakes wire may need to be reversed to suit the trailer. Check with a test light or VOM.