Wellll, I hadn't gotten around to giving them a call. I'm kind of sick right now, so my voice is a bit faint and hoarse. So I asked my dad if he would call Axiom for me, and he brought his multimeter, just because he likes figuring stuff out. Well, another one of the fuses was bad, despite the green light coming on. We replaced that, and the subwoofer is working now.

Duh.