I dont know what part of Harris County you live in but I
would take the trailer to a national brake repair shop
that installs electric brake controls and electric brakes
and have them spend an hour with it and they will
most likely find it for you and fix it.
An hour of shop labor and it shoud be fixed quickly
I would think.
I’m going to do some calling around and see if I can get it in sooner somewhere else to at least get a diagnosis without a 2 week weighting period.