1999 Nissan Frontier Trailer Wiring | etrailer Fastest shipping available and a lowest price 1999 Nissan Frontier trailer wiring guarantee. Expert lifetime technical support on all purchases. Complete 1999 Nissan Frontier Trailer Wiring installation instructions and customer reviews. Call 800-298-8924 to place your order or order online at etrailer. 1999 Nissan Frontier Hitch Wiring | Harnesses, Adapters Nissan Frontier 1999, T-Connector 3-Wire System with Converter by CURT®. For Models without Tow Plug, 3-wire System, Location: S1/S2. This provides all you need to connect a trailer to the tow vehicle.