expedition

i have a 1998 ford expedition.i just want a small system with a new radio that has aux plug.i thought this would be simple.....i cannot find the harness to interface with the factory amp for the premium sound.any help from anyone out there would be great.

I just got through installing a Viper 5901 in my 2003 Ford Expedition everything went just fine but now when I press unlock all my doors unlock. I had priority unlock with my factory keyles entry unlock once for driver door unlock twice for all other doors, I was wondering if anyone knew how to...