Today out of the blue the radio on my '01 HSE started to squeal loudly(sounded kind of like the tone you get for a bad weather report). I tired to turn it down and change the station and that had no effect, so I pulled over and shut off the engine and it still continued. Needless to say it was a long ride home, and I'm surprised I didn't have dogs chasing me lol. The squeal seemed to mostly be coming from the right side door tweeter. The nav was working fine, and the head unit functions were all working, just no sound but the loud squeal. I had to unhook the battery to get it to stop, and everything went back to normal after I hooked it back up. Any ideas on what might have happened?