2019 Toyota Tacoma Trailer Wiring | etrailer Separate wiring system - brake and turn signals are sent along separate wires. A powered converter module is required to safeguard the vehicle's wiring and to provide enough power for the trailer lights. T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector Shown on 2017 Toyota Tacoma Toyota Tacoma Trailer Wiring | etrailer Today on our 2013 Toyota Tacoma we'll be having a look at and installing the Tekonsha T1 Vehicle Wiring Harness with Four Pole Flat Trailer Connector, part number 118496. Here's what our wiring looks like installed. This wiring will give us the basic lighting functions that we need as required by law in order to safely tow a trailer.