Do you have the connectors from the donor vehicle? If so, cut and splice the donor connector into the factory wiring on the drivers side. You'll have to run new wired to the passenger side. Make sure the size of the wires are large enough and fused correctly.
I added a power drivers seat to one of my Explorers, ran wire from the battery through the firewall to the seat. Fused near the battery. If I remember correctly it was a 30A fuse... I know these motors take alot of juice, but as I type that it seems large.
You might be able to splice wires into the drivers side and run power to the pass side. Just pay attention to wire size and fuse.