How to Install a Horse Trailer Brake Plug
- 1). Locate the horse trailer's seven-conductor harness; usually the harness can be found attached to the trailer tongue.
- 2). Use a box cutter to free the first one and a half inches of the harness' outer sleeve from the seven inner conductors. Take care not to cut into the insulation protecting any of the separate wires.
- 3). Use wire strippers to remove a half inch of insulation from each of the separate wires. Twist the bared copper strands of each separate wire between your fingers, making seven tight braids.
- 4). Remove the outer casing from the round seven-pin plug. Some cases are held in place by a tooth that must be freed from a receiver, others by a single screw near the larger end; use a screwdriver if necessary. Slip the case over the harness, smallest end first.
- 5). Determine whether the inner terminal hub is marked with the names of colors or terminal numbers. The markings should be embossed into the plastic of the terminal hub, one color or number adjacent to each terminal. If the embossings are the names of colors, match the terminals to the matched color-coding of the individual wire's insulation, black to "Black," yellow to "Yellow" and the like.
- 6). Connect the wires to the terminal hub in the following sequence if the embossing are numbers: white to terminal one, blue to terminal two, brown to terminal three, black to terminal four, yellow to terminal five, green to terminal six and purple to terminal seven (in the center).
- 7). Slide the plug case back up the harness and secure it in place.