Trailer Wiring & other Towing Accessories - AutoZone If your vehicle did not come with a factory installed wiring harness: Your vehicle may have wiring plugs in place to help you install trailer wiring. Click the diagram on the left to show common locations for wiring plugs. Read your owner's manual and check your vehicle thoroughly before cutting or tapping into any wires on your vehicle. Trailer Wire Harness and Connector - Best Replacement Get the job done with the right part, at the right price. Find our best fitting trailer wire harness and connectors for your vehicle and enjoy free next day delivery or same day pickup at a store near you!