Junior FC Racer....let me know if you get your problem resolved...I also have a "91 vert with very low miles. This is the second time the headrest speakers have stopped working. Several years ago the dealer replaced the amp...it has now stopped working again and now the amp is now longer availible from Mazda. I am looking for someone to rebuild/repair the amp. Any solution to your problem would be interesting for me to know. Thanks.