Brake controller plug

LaTriker wrote:
I would like to use the 12 volt positive and ground wires on the brake controller plug to power a 12 volt plug. Does the brake controller plug have 12 volt positive and ground wires? If yes, which wires are they?

It definitely does. I can't say which wires they are, and I don't know if the positive lead is hot with the key off or not, or if that matters to you. And please don't take this personally, but if you don't have the tools and knowledge to quickly answer these questions yourself, (it would take maybe two minutes tops with a meter or test light) you will likely have much more satisfactory results taking it to a professional for the 12 volt plug install.

DrewE wrote:
On my twenty year older E-SuperDuty chassis, there's another accessory plug under the dash ...

Wiring has changed drastically since then ! The Ford Smart Junction Box (SJB)/Body Computer Module (BCM) brought in many changes.

You really need a factory wiring diagram !

On my twenty year older E-SuperDuty chassis, there's another accessory plug under the dash (in addition to the brake controller one) for the unfinished vehicle upfitter--the motorhome maker--to connect in lights and such. That has a couple of 12V circuits, among other goodies. I suspect you have a similar setup, and I'd think that would be a more logical place to get power from than the brake controller connector.

LaTriker wrote:
My RV is on a 2018 Ford E450.

If you have a factory integrated brake controller, do not rely on any wiring diagram that is NOT directly from Ford !

Check out etrailer.com for brake control hookups . They show you wiring diagrams and videos.

Stick a pin into the black and use a meter to ground to be sure.

The brake controller plug is much easier to get to.

You should be able to find 12v positive somewhere under the dash. Why take it from the brake controller?

On mine the black is positive and white is negative which plugs into the controller.

My RV is on a 2018 Ford E450.