03 Mustang Aftermarket Radio Installaion Issues - Mach 1000 audio system?

I have a 2003 Mustang. I believe I have the Mach 1000 audio system, but there is no Mach 1000 on. However, the radio is a double din. I recently took it out and hook up an aftermarket Pioneer radio. However, after I replaced it, no b came form my two back sub woofers/amp. I've tried 3 different wire harnesses. I'm starting to think that it is impossible to connect these sub woofers. Someone please help. I've wasted so much money trying to get this to work.