1997 Premium sound-need amp level adapter
 

Recently bought a 1997 Ford Expedition and need the wiring harness so I can ad my aftermarket MD player/ CD changer. It has the premium sound system which I assume means it has an external amp to the radio. So, I need the wiring harrnesses for it. I need the rectangluar plug, and the square plug in either pre amp, or wired for amp level. (My head unit has all the pre outs for front, rear, and sub). Anyone have one out there, or can you point me in the right direction with a part number? Thanks alot!!