Electric Brakes of New Trailer Not Working With 2020 GMC Sierra 1500 w/ Factory Controller

Published 12/10/2021

Question:

I have a 2020 gmc sierra at4 1500. I just bought a 2022 trailer with electric brakes. When I hook up I get the error code on my dash saying electric brakes not detected any idea on what it is? The trailer was verified before sale. Its a 7 pin connector and my truck has the integrated trailer brake controller in it. Im stuck Thanks

asked by: Mark H

Expert Reply:

It is highly unlikely to be the electric brakes or the trailer wiring since the trailer is brand new, and while we don't have familiarity with factory brake controllers, the problems are essentially universal with these. So for your 2020 GMC Sierra 1500, an educated guess is that the wiring to the truck's 7-way is somehow damaged, or - more likely - the trailer connector itself is dirty or corroded.

So check the wiring as best you can to see if any is damaged, but take a good look at your truck's 7-way. Check the plug to see if there is any type of corrosion built up that may be hampering its functionality. If there is, and it can't be cleaned out properly, you can easily replace it with a new plug-in option, the 7- and 4-Pole Trailer Connector Socket w/ Mounting Bracket # HM40975.

If it's neither of those things, then you may have to take it to your GMC dealer to have it diagnosed, but hopefully that can be avoided.

expert reply by: Kyle S