How to Wire a Trailer for Vehicles

by Contributing WriterUpdated June 12, 2017

When towing a Vehicles you must adjust your speed to compensate Vehicles the reduced braking and cornering of the Vehicles. One way to mitigate the reduced stopping ability is to use a Vehicles equipped with an surge break system. This system uses the stopping momentum generated to apply a Vehicles break. The additional brake Vehicles disengages the Vehicles brakes when the Vehicles is reversing. Wiring the Vehicles this type of system is a little more complicated than Vehicles standard Vehicles lights.

Under The Hood:

 How to Wire a Trailer for 5 Wires

Attach the 5-way connector the the trailer's tongue with the cable ties. Leave enough wire to make it to the vehicle's connection, but not so much that it will drag on the ground when towing.

Assess how the trailer's lights and brakes are electrically grounded. The most common system is through bolts which attach them to the frame of the trailer. If there is no ground wire at the lights, this is most likely the case. If the lights have a separate ground wire, you will need to attach that to the bare metal of the frame. This can be done by sanding off the paint and fastening the wire with the drill and self-tapping screw .

Attach the white wire at the 5-way harness to the frame of the trailer in the same fashion as Step 2.

Attach the brown wire to each of the trailer's marker lights with the butt connectors. A butt connector works by placing the two stripped wires in either end and compressing with the pliers. Gently tug to assure a tight connection.

Attach the green wire to the right turn signal and the yellow wire to the left turn signal with the butt connectors.

Connect the blue wire to the trailer's actuator with the butt connectors.

Wrap all of the connections in electrical tape to protect them against the elements.

Items you will need

  • 5-way trailer wiring kit

  • Sandpaper

  • Drill

  • Self-tapping screws

  • Cable ties

  • Insulated butt connectors

  • Electrical tape

  • Pliers

 How to Wire a Trailer to a Silverado 1500

Crawl underneath the Silverado. Locate the stock wiring harness end, which is above the spare tire. Pull the stock harness out from the spare tire area with your hands.

Pull off the cap on the factory wiring harness by depressing the tab with your thumb and pulling off the cap. Secure the trailer wiring harness mounting bracket into the bottom of the bumper with the self tapping screws and a drill. Run the trailer wiring harness through the bracket, then bolt the end to the bracket with an flathead screwdriver.

Plug the factory harness into the trailer wiring harness. Zip tie any excess wiring to the hitch.

Test the lights to ensure they work properly, prior to taking the trailer out on the road.

Items you will need

  • Trailer wiring harness kit

  • Zip ties

  • Drill

  • Self-tapping screws

  • Flathead screwdriver

 How to Wire a Trailer to a Subaru

Installing the Wiring Harness

Buy a trailer wiring kit designed for your model of Subaru. Some will come with adapter plugs.

Find the towing electrical plug-in in the utility well on the side of the Subaru's trunk. The utility well is located to the side of the spare tire. Some Subarus will have the electrical plug-in inside a wheel well. Remove the panel covering the utility well and find the electrical plug-in. It will have eight pins.

Plug the wiring harness into the plug-in. The wiring harness can stay inside the utility well out of sight when not in use. Attach the wiring harness to the inside of the utility well with double-sided tape or the adhesive on the side of the coupling if your wiring harness comes with it.

Lead the wiring harness out of the utility well through the fifth door or the trunk lid. The insulation between the trunk lid or fifth door and the body of the car will close over the wiring harness with no problem. Replace the panels covering the spare tire and the utility well.

Plug the wiring harness into the trailer adapter.

Items you will need

  • Trailer wiring kit

  • Double-sided tape

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