Mover, yesterday I went ahead and drove over to the RV in storage a few miles away since my memory doesn't always work as well as I think it does. But, I took a pic.
The pic shows the wire (w yellow solderless eyelet) I spoke of in the photo attached to the top post of the TH1020 box. The large cable goes directly across top to the positive post on the chassis battery. As someone else said in another post same subject, there is always power on that cable unless you have a battery disconnect in-between.
You will see the fuse holder about 3 inches from where the 10ga cable attaches. That contains a 30 amp fuse and that's what came loose and killed the power to on brake system. The power was constant and ran the compressor on the BrakeBuddy. The installer tied into the 7 way connector to use the power to supply the system.
As said before, not sure your RV is setup this way but it may help. Thx, Dennis.