So I had a wiring issue with the trailer. When I installed the brake controller in the van last weekend and tested it with the trailer...nothing. The controller didn't even recognize that any trailer brakes were hooked up. Uh Oh. It had to have been either an issue with the van, or an issue with the trailer. The issue was compounded by the fact that I wasn't getting 12V power from the van to the trailer, so things like the refrigerator wouldn't work while on the road, and the battery wouldn't charge.
I spent this weekend with a multimeter and a circuit light. I determined that the van wasn't the issue, that all the signals were coming out of the van plug as they should. Then I went at the trailer, and ended up pulling my hair out. The trailer is 13 years old, and has had multiple owners, and it seems like someone has already been at the trailer wiring with some snippers and a crimping tool. Not my idea of fun. Wiring isn't my strong suit, either. Anyway, I went on to the popupportal forum and asked for some help. One member posted a wiring diagram for the brakes, which helped me to no end. Turns out I had a bad ground. I ran a new ground wire from the brakes to the front, and lo and behold:
The brake controller recognized the brakes, AND I have 12v power from the van to the trailer, so all my accessories work while on the road. I just got back from a road test with the trailer hooked, where I calibrated the brake controller, and confirmed that the brakes actually work. I'm so happy now. Van and trailer are now 100% ready for our upcoming road trips.