Driver's Side Front Window Problem, please help!!!

I'm having a problem with getting my driver's side front window to go up. I have replaced the window motor, the control switch, and the window relay in the right fuse box. I have even went to the extent of seeing if the window motor was faulty, and connected it to the passenger front connector in the door. The motor isn't faulty. It will go down, but it seems like there isn't enough voltage going to the motor. There's continuity on the connector in the door. If anyone can help me, please let me know. I've ran out of ideas.