Joan - I don't have my manual handy, but I'll check it out tonight.

We had the basic 6 disc in dash changer with the 4 speaker system. I would have thought that if the automatic volume control was enabled and causing this problem then I would have also noticed it performing normally and adjusting the volume when I accelerate or brake.

I'm 99% sure that this wasn't happening, but I'm not going to bother putting the unit back in to test it out, there were other reasons to get rid of it as well