Well, I finally got it all figured out, I found the best way to install a new Hu in place of a non-bose in a '93, is to not even bother using the factory amp, or trying to tie the amp wiring harness together to get the rear speakers to work right. I just ran new speaker wire directly from the HU, to the rears. Took about 1/2 hour and it sounds great, no more ground or amp problems. If u are just replacing your HU and Speakers, I think this is the best way to go. BTW, the non-bose HU is made by Clarion and the CD is made by Sony, they are just about as reliable as Bose is!