Army_Monkey

I tried searching, but the phone app makes it extremely difficult because I couldn't narrow it down to just this section.
I bought a 20' car hauler to tow behind my '13 STX with the factory tow package. When I went to pick it up, only the running lamps and electric trailer brakes work. The turn signals and brake lights would not come on and have no power at the plug. I checked the plug by the spare with the same result. I have an aftermarket brake controller that is showing continuity.
Service dept is telling me that it HAS to have the OEM brake controller and be programmed because that is where the trailer control module is. I'm having difficulty believing you can not tow with this truck without it, because not all trailers need one. I went ahead and ordered the OEM one anyway because I want to integrate it into my dash, but is what I'm being told correct?

kidastra

iTrader: (1)

Obvious 1st question would be, did you install the relay and fuse under the hood, most trucks aren't installed on delivery and are located in a little bag inside the glove box.

2nd question did you check the fuses for the other lights? Multiple fuse locations for the trailer for the different lights

And I believe they are wrong, plenty of people use aftermarket brake controllers

Army_Monkey

Every relay and fuse I could find listed as belonging to either the trailer light wiring or the trailer brake controller are all present and in working order. I can even hear and feel the relays clicking for the trailer right/left turn signal when the turn signals on the truck are on.
Trailer brake controller is hooked up to the OEM wiring as most are. It works and has no issues with activating the brakes or a signal at the plug.

kidastra

iTrader: (1)

If I understand correctly you have turn signal at the plug?! If so your wires on the trailer need to be looked at, a simple 7pin/4pin trailer tester would help a lot at diagnosing, or a simple test light

Your first post mentions no power at the plug, I would inspect your wiring for the brake controller, even better would be removing the brake controller completely and seeing if that fixes the issue.

Really does sound like a burnt fuse though, #73 under the hood. Even if it looks good, replace it with another 20amp fuse to be sure

Army_Monkey

Thanks for the help, after taking it to another dealership, the tech poked around for a good ten minutes, saw nothing wrong with anything or the fuses, but did exactly what you said and replaced #73 just to be safe.
Needless to say, but everything works perfectly now. The fuse was blown so minutely that the only way to tell was by testing it. I definitely learned from this experience.

RES4CUE

For what it's worth, the OEM controller is awesome and integrates way more than aftermarket.

kidastra

iTrader: (1)

Awesome, glad it was a simple problem

4.6Intruder

I was in the process of installing the oem brake controller and the 7/4 pin connector with the Ford pigtail harness to connect the chassis harness to the trailer plug, but then realized the chasis harness does not have the trailer brake wires. I have the harness in the dash for the controller, but the harness that runs down the frame doesn't have the wires needed to work the trailer brakes. I can't find any wiring diagrams so I can run my own wires from the plug to the controller. Not sure if the plug wires go into the power distribution box under the hood, or goes directly to the controller. Sorry to hijack, but created a thread about this with no response.

jkenprice1

I find it hard to believe you don't have a place to plug the 7 pin harness into. Every truck I've had since the 90's has had. On my 13, the wiring harness runs above a cross brace and the socket for the 7 pin plug is kinda hidden by that brace. I had to take down the spare to get room to get to the wiring harness. I'd bet you have a plug up there.

kidastra

iTrader: (1)

Not sure if this helps but I'll add it anyways
https://www.etrailer.com/question-21527.html