The guy who gave us the walk-through indicated that the converter/breaker panel would show which fuse was blown due to the red LED. That is true, if there is a load. I enlisted my 5-year-old to watch the panel when I pressed the switch from outside the trailer. He then could tell me which LED would light up when I pressed the extend position. Sure enough, a blown fuse (unlabeled, of course).
Which brings up the question - How many spare fuses do you carry? Clearly, I learned today (in an easy way), that I need to carry some.
Now to look through the mods and tips to see about the 'battery disconnect' modification.