Sorry for the delayed response. You all had me on the right track and saved me a lot of time troubleshooting wiring on the trailer. It was the controller. On Saturday morning I tried the voltmeter tests. I was getting totally inconsistent results. No reading on the initial battery voltage test, full reading on the running lights, nothing on the brake test. There were inconsistent readings and didn't have complete confidence in my multimeter, but it seemed the controller was not sending any power. So I hooked up and tried to drive, and my issue of locking was gone. That is because it wasn't applying any brakes. I tried raising the level, and the controller indicated "no trailer". So definitely the controller. I took it into Ford and they have confirmed it was causing shorts. I will post the full diagnosis when I get it back.
Thanks again for all of your help. I seriously would have been trying to chase wiring on the trailer shorts without this post because I just assumed being a fairly new truck and controller that it wouldn't be that.
