Explain how emergency trailer brake gets power?

I bought the camper new from dealer and the only rewiring would have been by me. I'll have to do some testing to see what happens. If I remember right, the wire from the back of the breakaway switch went back into the junction box on the frame where the main 12V supply to converter/power center.
I found a photo I took for another purpose which I've zoomed in and cropped down.
I think the gray wire(s) are from the breakaway switch.