Thanks, I did not know that...that's the most immediate thing I can try since I lack a set of tools at the moment.

The problem transformed since my last post, however. My 4-channel hasn't put out sound in the last three days at all, and I kept an eye on it while turning my radio on and off. The sub amp turns on, no problem, and I reinforced the remote wire connection (which is just the 2 leads from each amp crimped together with the 15' wire). All other connections appear to be solid at the amp.

Now, the 4-channel's LED lights up upon turning the radio on, but then dims gradually and completely after a few seconds. There isn't a pop or any sound, really, but it does light up each time (so I'm guessing it isn't the remote wire). Should I check its fuse next?