stock sub woofer hookup to aftermarket st

i would like to know if anyone can tell or has diaigram of how to hook up aftermarket stereo with sub woofer outputs, but using  the stock subwoofer setup on a 2001 ford escape, lost in sub??????

Did you purchase the appropriate wiring harness?   If you did buy a harness but it did not have provisions for the factory amp to be connected, you have the wrong harness.  Carry your OEM radio into the shop you got the harness from, with the radio in hand they should have no problem getting you the right harness.

do you have a wiring diagram and i will hard wire it??

If you still have the OEM plug on the harness, connect the factory radio and using a meter determine which wire on the unused plug is the amp turn on wire.  Then with the radio still connected, check the resistance between the remaining wires and the chassis of the radio, there should be 2 wires that read very clost to 0 ohms.  Those 2 wires are the shield of the preamp signal leading to the amp.  There should only be 2 wires remaining, those 2 will be the signal wires that feed signal to the amp.