Ok guys, when I bought my truck, this was in a side pocket in my drivers side door, wrapped in plastic. My truck has the factory trailering package, but I have no idea what it's for. Any ideas?

 

I'd guess redundant package if everything else seems normal. I bought a Focus a few years ago that had block heater and additional plugable attachments bagged in the trunk. Trip to dealer got everything fixed.

 

It looks like a brake controller harness...

 

It's the trailer brake adapter harness. It is used to tie an aftermarket trailer brake controller into the truck's towing wiring. It connects to the same connector the OEM brake controller uses. If you have or intend to install the factory trailer brake controller it is redundant. I just threw mine in the glove along with the tailgate jumper plug and forgot about them.

 

Thanks guys 👍