2014 - 2018 GM Plug and Play Tow Mirror Wiring Harness Make all features on 2014+ tow mirrors work plug and play without having to buy costly harnesses ($300+) from GM. Works on all GM tow mirrors for Silverado and Sierra 2014 to 2018. Full install video and FREE SHIPPING. Get your towing mirrors working properly today. Running light, signal, cargo lights, and power fold. SilveradoSierra • Tow Mirror Wiring Harness : Exterior Feb 16, 2019OK, I am thoroughly confused. I bought a 2018 Silverado LT that is equipped with the DL8 mirrors. I bought a set of the OEM GM manual fold trailering mirrors with the turn signal, power adjust, back-up and running lights.I asked the dealer to get me the correct harnesses for these mirrors to work and they got me the part # 84290984 (Drivers) and # 84290986 (Passenger) harnesses.