I know this was ages ago, but the same thing happen to my ford power window switch. Last day, i have checked the hammer and seems that it also increases magnetic field. Any update on this one?sounds like the window motor armature has a parcial open or high resistance. It works ok w/ no load, but as soon as you make work hard,amp draw goes higher then the armture can handle. Placeing a hammer head next to the feild increases the magnetic field giving a small boost. Smacking it w/ a hammer may cause the open to close for a sort time. Either way the motor is bad.