Prodigy P3 Brake Controller Installation in 2018 GMC Sierra 1500 with Factory Tow Package

Question:

Have trailer equipment package with seven wire connector but no power to electric brakes terminal under dash. Manual states wires may not be connected. Had to connect wires on my 2008 but cannot find any info on 2018 connection. Please advise.

asked by: Steven K

Expert Reply:

Since your 2018 GMC Sierra 1500 came with the factory tow package it should have the completed wiring, with the 7-way at the rear bumper up to the completed brake controller plug under the dash in the passenger compartment. You're right that certain older model years had only blunt cut wires tucked up under the dash, without a connection port to mate with the square plug on the installation harness # 3016. Your installation of the P3 # 90195 should require only connection to the appropriate port using wiring adapter part # 3016. I confirmed this with my contact at Tekonsha.

It is possible that there is a missing fuse or relay in the engine compartment power distribution box. The online owner's manual indicates on page 382 that fuse location 1 covers the trailer brake circuit. I suggest first checking this fuse location. Install or replace the fuse as appropriate. The power box lid should indicate the correct fuse value, typically a 20-amp or 30-amp.

If all else fails you can always run your own +12V power wire to operate the controller. You'd just need a length of 10-gauge wire # 10-1-1 long enough to reach from the rear of the controller through the firewall to the battery, where it will connect through a 30-amp breaker # PK54230 to the battery + terminal.