Brake wiring shorted and smoked.

Your brake controller outputs a variable voltage base on how hard you are braking.. That's why it's called a "proportional controller" and the voltage is provided by the controller and TV.

There are "timed controllers" also, hopefully no one sold you one of those...

The breakaway is powered by the Pod's battery, and that's why it's unsafe, (and against the law in many/most places) to tow without a battery in place. It has no proportion or controller, it just, when that pin is pulled by the separation of the TV and trailer, sends everything it can to the brakes, so hopefully, it doesn't crash into anyone/thing.

The short can be located anywhere in the brake wiring. When that breakaway switch is activated, it sends maximum amps to the brakes. It's job is to stop the camper as fast and hard as possible, in case it has become unattached. So it energizes the entire system fully.

So you have the wires coming from the battery to the breakaway, the wires from the breakaway to the brake wires, the wires running to the brakes themselves. As noted above, the wires coming out of the brake housings are polarity blind. It's just a simple electromagnet, and the current can run either way through them. So start at the brakes themselves, and start following/tracing/checking the wires back towards the front of the camper. Replace or repair any wires that look iffy or are damaged.

This is kind of a basic TT owner skill.. "Stuff" hits the bottom of a vehicle way more often then we realize, and a TT has a higher number of hits because the tow vehicle is so close and can pick up stuff we don't even see on the road and bounce it under there, hitting exposed wires, tanks, etc.

.