In my 1997 4 door chevy blazer i now only have one working speaker left, along with the two tweeters on the dash but can't seem to figure out why. The speaker on the driver's side door cuts in and out once in a great while, and the two speakers in the back don't make any noise at all. I took off my driver's door panel and there wasn't anything obviously wrong, but i'm not too experienced with sound systems. any ideas as to what could be wrong would be greatly appreciated