2019 F150 Trailer Brake Controller Wire Size

Updated 06/27/2020 | Published 06/25/2020

Products Featured in This Question

Curt T-Connector Vehicle Wiring Harness with 7-Way Trailer Connector

(140)

$78.52

Curt Custom Wiring Adapter for Trailer Brake Controllers - Dual Plug In

(87)

$12.73

Custom Wiring Adapter for Hayes Brake Controllers - Dual Plug

(16)

$19.31

Question:

I have the plug that shipped with my new F150 in the glove box to install an aftermarket brake controller. I am only pulling a single axle trailer so just 2 brake units. The Trailer brake controller instructions I see on your site show to use a 12ga wire for the ground, power and brake wire, but the adapter plug in the truck is using very small wires. Do you know if they have a relay to carry the high current to the trailer brakes, or should I just start from scratch and wire the controller in as if it did not have the plug built into the truck?

asked by: Ralph S

Expert Reply:

I'm not entirely sure a relay is used on that circuit, but it would provide a good explanation for the smaller wire gauge used on the factory pigtail. There's really no need to hardwire the controller. If the small wire gauge concerns you, there's an aftermarket one available, part # 22292.

The black power wire and the blue brake output wire are both 12 gauge and the red stop lamp switch wire and the ground wire are both 16 gauge. This harness is designed for use with Tekonsha brake controllers, but we also offer the # C51436 for Curt controllers, # HM47845 for Hopkins, or # HA81794-HBC.

I've linked to a video showing a brake controller install on a 2018 Ford F150. The procedure for your truck would be the same.

expert reply by: Mike L