I just bought an 07 Ford F150 Lariat Supercrew and then purchased an Audiophile powered sub and correct radio. Locating the extra connector behind the radio was easy and the new radio is working fine. The problem is I can't find the other end for the sub. I even took it to my Ford dealership and they took out the back seat and couldn't find it. Is it possible to have the connector at the radio, but stopping somewhere like the junction box in the LH kick panel? Seems like it has to be somewhere? I thought regardless of whether you have the Audiophile System, you'd have the connectors for it in the wiring harness. Am I wrong?
Any help would be appreciated.

 

Look for the little cut out in the carpet under the rear driver's side seat. The hookup will be attached the the floor with one of those plastic clips. Reach your fingers inn, feel around and yank it free.