I took the book in from a 97 to where the King sits and for those so inclined it looks like the black wire on the window motor is the one you want. This is for power up. You would need a large gauge wire run from the battery etc. through the jamb and into each door you want to do. The one end of the existing black wire from the switch then could pull it the relay and juice the motor with your new power supply. A first test could be to take the door apart and time the window; then cut the black wire by the motor, and just touch a larger gauge wire from the positive to the motor side timing this. I am happy with mine as is.
Bill
Bill
