[BB_TX]

That is a hard one. The breakaway is an important safety feature in the event a trailer somehow came loose and should not be disabled. Not likely a trailer will come loose, particularly on a 5er, but possible and does happen. Fusing that line is not a good idea as you would never know if the fuse was blown disabling the safety function unless you put in a monitoring system for it. And ultimately you were at fault even though you did not know what you had done at the time.
I seem to remember one other instance of someone posting about a similar issue with that wire. Don’t remember the details. But it seems to be a very rare event.