[kbobak]

I am experiencing the same issue on my 2005 Sovran 3600. The head unit does derive power from the sub woofer through a 15 pin D sub cable running between them both. I have had the head unit out it isn't the easiest but it does come out. The power to the sub on my boat comes from a power conditioner (why? I don't know) below and behind the fridge. I am working through this problem right now. In my case the AC outlet breaker trips. The power cord for my sub woofer routes behind the cabinets. I am waiting on a replacement power cord to come in and plug it into a different location to bypass the power conditioner and isolate the problem prior to ripping a bunch of stuff out unnecessarily.