I just bought a 1990 Mustang GT and the it looks like the previous owner tried to hook up a new stereo on their own but couldn't figure it out so now i need help fixing his mistake. So when i got the car only the passenger side door speaker was working so i removed the stereo to see what was wrong and it turns out a lot of the wires have been cut and spliced and only the one speaker was hooked up. I decided to undo everything and start over and while i was at it i decided to remove the factory amp. Now i need help locating which wires to use to hook up the stereo as well as bypass the factory amp that was under the AC controls. There is two square wire harness plugs that went to the factory amp and the other wires that probably went to the factory stereo that were cut and i don't know what wires are which, it seems like everyone says that there are certain colors but they never match up to the wires in my car. Is there a wiring harness that will bypass the amp as well as hook up the stereo, I can't seem to find one that looks like it will work. HELP!!!

 

Best to just test every wire and go from there. I had to do it. It'll be very very time consuming.

 

check out page 2 of my cardomain page. You want to find a harness that looks exactly like the one I point to on that page and it should have been plugged into the factory amp up by the glove compartment. That is your speaker harness, you can use a metra 70-1770 or scosche FDO2B harness to plug into it.