Trailer Wiring Harness Installation - 2012 Nissan Frontier May 16, 2012How to Install a Trailer Wiring Harness on a 2012 Nissan Frontier. Today on 2012 Nissan Frontier we are going to install the tow ready T1 connector part number 118525. This is a two-part harness. The first piece we'll be adding to the passengers side kick panel. First, we'll remove the passenger's side threshold trim then the kick panel.4.9/5(495)Category: Custom Fit Vehicle WiringBrand: Tekonsha 2012 Nissan Frontier Trailer Wiring | etrailer Call 800-298-8924 to get Expert Service ordering a Trailer Wiring for your 2012 Nissan Frontier. Complete installation instructions and lifetime technical support on all Trailer Wiring purchases. Lowest price guarantee on accessories for your Nissan Frontier and the fastest shipping available.