Please help!

Okay, I installed a new head unit, but I have lost the FM cable, I think. I have one, but I think it is the sirius wire. Where would I begin looking for the FM cable. I have dug behind the dash alot, but cant find the other cable, be it the FM or the sirius, I only dug out one. It fell behind somewhere when I was cutting the dash.

Also, maybe I just need to power the blue wire from the scosche adapter, anyone had experience.

Please help, I am beyond frustrated.

Thank you,
Wader.