I seem to recall my old EP500v2 also had this switch, and I think many times when I was trying to tweak all the settings (phase, crossover, etc.) I tried this setting out of curiousity, but it didn't do anything. I seem to recall the Load setting is for accessing the internal processor, probably at the factory.
It would be interesting if they had a setting that would disable the sub, if that is the case it should not have been included as a selection.
Anyway, my suggestion was to unplug the power AC cable for 5-10 min or so...sounds like you've tried that... The only thing is to contact Axiom which sounds like you have done that...
Good luck
