2000 Eddie Bower Explorer Factory Sub

I put in a deck today (DEHP6800MP) the noisy one I took out of the Honda I last posted on. I used a metra harness# 70-1771 This adapter has NO amp turn on. I know that there are ways of integrating the factory amp (so the factory sub will play, Sub ONLY) But I have no idea how to do what the customer desires. I am satisfied with the bass from the pioneer head....but the customer asks..."did you make the sub work" I did not put my head in the rear of the Explorer to verify the sub was, or, was not working.....it sounded great.

Do I need to use a 70-5700? the factory radio has 3 plugs, all rectangle in shape (none of the stadard ford plugs like on a 70-1770)

Any GOOD thoughts?  

P.S. in this business for YEARS.....and right now I feel stupid...

This is the part # that Matt @ metra gave me. My complaint was, on line, the ONLY harness adapter they give reference to is the 70-1771. Thanks for the input gentlemen......