I'm trying to install a mach 460 in a 1988 GT with factory premium sound. Of course. In 1988 this could be premium

.
Anyway!
I wanted to keep my car as original that i can and mach 460 is enough for me.
The kit is from a 2000 mustang. I have everything needed (wiring harness, amp, speakers, cd player, radio, etc)
When i hook all the system every thing look like to work fine except that i don't have sound
First i had to remove my factory amplifier to hook my radio and i have to re-adress one wire in the wiring harness to fill an hole in the master power harness.
I've verified all my connection but i still without sound.
What can be the problem????