I have a problem with the passenger door electric window on my '99 F150 lariat. It won't roll down. I will temporarily fix it by pulling down on the glass while operating the switch. After about 15 minutes of doing this the window will finally come down, but in about two days the problem comes back. I know the motor is working because it draws on the electrical system while I'm working with it. It's like the window is physically stuck. I've checked the weather stripping and it seems clean and unobstructed. Any help would be appreciated.