[sd_boxster]

If air's moving, the mid-mounted sub is working. The Bose system (or the "Blows" system, as I've seen it referred to) is really not that great. I assume you also have the door-mounted subs?

I have taken the rear speaker out for a week or two a few times, and the bass response doesn't change dramatically. It does contribute, but not to the extent you'd imagine it would, given its presence in the cabin.

So, the good news is that yes, it's probably working... the bad news is you own the same crappy stereo I own.