2002 intermittently dead rear speaker...

The other day my passenger side rear door speaker was playing just fine, then cut out all of the sudden. It doesn't rattle like it's blown, it just died. It wouldn't play the rest of the day, then when we got back in the truck yesterday it was working again. Well, for a little while anyway, then died again. Now it isn't playing at all today. I know there were some changes in the Bose system from '02 to '03. On these systems, does each speaker have an individual amp? I know that's how it was in my '99 Eldorado. That's the only reason I can think of for it behaving this way, is that an amp is cutting in and out. Any thoughts?