Best Trailer Wire Harness and Connector Parts for Cars wwwzone››Trailer Wiring And ElectricalEquip cars, trucks & SUVs with Trailer Wire Harness and Connector from AutoZone. Get Yours Today! We know our parts and products. Wiring Harness Tow Bar Wiring | etrailer Quickly and easily connect your towed car's lighting system to your RV to activate the signal lights required for towing. This custom harness plugs directly into existing wiring - no cutting or splicing. Operates as combined lighting system.