Trailer wiring back of truck, help needed (2011 xlt el)

[callwill]

I thought the truck was already set up (never really looked at the existing wiring under there until today). There was a 7 pin connector already in place, everything i towed so for was a flat 4 using a 7 to 4 adapter. Decided that it was time to tow the camper. I plugged in my brake control unit under the dash. I backed up to the camper and plugged it in. All the lights are fine, but no brakes per the controller monitor and no charge feed. At first i thought it was on the trailer end and have been messing around with it. I finally got under the truck back end with a meter and tools looking for a problem wire or connection or 2. The PIcs show what i found after removing yards of tape. Do i start cutting open the existing harness in hopes of finding the other 3 wires i need for the 7 pin? That harness disappears somewher forward of the spare tire
As you can see, 3 wires from the mounted 7 pin (blue (to brakes?) yellow (?)and black(back up lights?) were unconnected and just folded under the tape. I guess i should check those for continuity to the connector pins to be certain what they were for. The truck has 2 leads coming from the harness, the one with the 4 pin connector on the end and another with a single black wire protruding from it that looks capped with something.

 

[callwill]

After thinking about it, wondering if that extra capped wire is from the brake controller. Can anyone confirm that?

Update: That wire was the lead from the brake controller. Everything is connected and working now. Thanks everyone!

 

[callwill]

So next up, im thinking i should run a 12v hot to the 7 pin plug. Do i take that direct from the battery with a relay, or is there some place closer and easier? Maybe from the rear power plug?

 

[Steve Hartman]

First off, you need to run your brake wire (blue) to your brake controller. That controller decides how much voltage to send to your trailer brakes based on the amount of pressure you apply to the brake pedal. Second, your yellow wire operates your left turn signal. White is your ground, green is your right turn signal, (NOTE: yellow and green are also for your brake lights!) brown is your running lights, Black is your 12V power wire that can be used as an accessory for your trailer. Trailer battery charger? (NOTE: Some vehicles use RED instead of BLACK!) If you really want some help, go to www.bing.com. In the upper right hand corner right under the X for the close window, you will find a multi-colored icon. Click it and wait. Your screen will split. That's Co-Pilot on the right, MS Edge's AI that will become your best friend! Type or click the mic and ask her anything! LOL! No, I'm not kidding!

 

[07Tjherr]

Hello, what I did on 2007 was found the spot for the fuse and relay under that hood then I found the wire that was for the circuit. For me it was in a plug on the driver side under the hood on top of the fender well. Mine was orange then I ran a wire to the back I put wire loom on it for added protection. With to relay and 30-amp fuse in place it can on only when the ignition is on. I hope this helps