Trailer wiring harness | Tacoma World wwwmaworld››3rd Gen. Tacomas (2016+)Jul 25, 2016I have the same issue. I already purchased part number PT725-34140 (shown below), which fits perfectly in the port next to the license plate, but I can't find the wiring harness to connect this part to the existing wiring on a 2016 Tacoma. I have called the dealership and Toyota customer service and neither of them could help me. Amazon: tacoma trailer wiring harness wwwon›Search›tacoma trailer wiring harnessAmazon: tacoma trailer wiring harness. ONLINE LED STORE 4-Way Flat Wishbone-Style Trailer Wiring Harness Kit [25' Male & 4' Female] [18 AWG Color Coded Wires] [SAE J1128 Rated] with 4 Flat Connector for Under or Over 80" Wide Trailers. 4.6 out of 5 stars 113. $12 $ 12. 99.