Dead Circuit

On our recent month long trip which we returned from yesterday I encountered an interesting problem.

We were at Mueller State Park in CO, on the back side of Pikes Peak, a campsite that had electricity.  After plugging in I checked the batteries voltages and noted that the one plugged in only read 12.48 volts, not the normal 13+ volts when plugged in.  Proceeded to unplug from the pedestal when the fridge began beeping.  I went to transfer to propane, but nothing.  No lights, tried the slide on the 177, dead, nothing.  Absolutely nothing worked - as if the battery wasn't hooked up either.  The interesting thing is that the slide worked just 5 minutes prior.  Checked all fuses, including the two 40 amp fuses - all good.  No red L.E.D. lights were lit on the converter either.  Checked both batteries and switched to the alternate battery which read 12.72 volts, again no power anywhere.  Proceeded to check the ground and that was good.  Called my brother (a mechanical engineer and also good in electrical issues) in Michigan to help.  Unplugged the toggle switch for the slide and checked ohms, resistance was found meaning the motor was good.  Everything pointed to the converter.  Fortunately when we ordered this 177 back in January 2011 it came without the following: A/C, convection/microwave oven, entertainment system.  Brother told me to remove the wire on the converter that went to the slide and move it to either of the two open circuits available which I did.  After that everything worked normally for which I was very thankful.  The only things still puzzling is when the 30amp fuse on this circuit is removed the red l.e.d. light does not come on, maybe that light doesn't work at all? Also, why did everything die and then magically work again when only 1 wire was changed to the open circuit? Anyway, if this happens again on any other circuit there is still have one more option (open circuit) to use before having to replace the converter.  Or maybe, before something worse happens maybe the whole converter ought to be replaced?  What do you think?