2004 Ford Explorer audio wiring

I'm trying to install my subwoofers to the stock audio system in my 2004 Ford Explorer. I've been unsuccessful finding any wiring diagrams. Can anyone help. There seems to be a stock subwoofer in the rear which I'm having trouble accessing. There might be a small amp and some wires I can connect to directly in there. Or I may have to go all the way to the head unit, but even then I don't know which wires are the rear right and left. Any ideas? Thanks Clayton MillsClayton Mills

If you have a stock sub, you need to get your signal there.  If you're unsure of how to get to the sub, I recommend taking it to someone else so you don't accidentally break something.My ex once told me I have a perfect face for radio.