Audio Systems: Car Stereo, cadillac seville sts, cadillac seville

Question
I have an 89 Cadillac Seville STS with a Delco sound system in it (factory).  Only the rear driver-side speaker works.  If I adjust the balance to the front or to the passenger side all the sound goes out.  The car is like-new and I bought it off some old lady who was the original owner and barely used it, so I don't think they're blown.  The speaker that works sounds perfectly fine to me.  I was wondering what I might be able to do to find the problem, or if you know the answer please let me know how I might fix it.  Thanks

Answer
Andrew,
The problem may be due to defective amp IC's inside the stereo. Please give me the complete model number off the stereo. You will have to pull the stereo out of the dash to see the model number printed on a sticker. In the mean time you may want to check out the follow site for the wire colors of each speaker feed wire. (www.streetdreams.com) You can use a AA battery with wires attached to it so you can put it across each speaker line and listen for a click as you touch the battery across each speaker line. A click will tell you that each speaker is OK.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net