Blank and Black/white wire power seat question

[Peanut74]

I wanted to replace the seats in my 97 Ford Ex and my friend gave me some seats he had. The seats turned out to be out of Ford Escort SOHC and not an Ex. There are two wires a black and a black with a white trace and my question is what does each of the wires do? I am assuming that the ground is made through the chassis and one is power but that still leaves one wire unaccounted for.

 

[Peanut74]

Well I think I got it figured out. The black wire is for ground and the black with white trace is for power. Turns out the motors have a heavy draw and that is the reason for the heavier gauge wire and separate ground.