RE: K5 power window problems
Actually, I would hotwire the motor to verify that it isn't a power delivery problem, but I am going out on a limb and state that the motors are probably toast. Typically in the older vehicles you either get power through the switch or you don't.
This could also be a window out of alignment, making it bind. If you find that if you wiggle the window as you try to raise/lower it and it works better, then you may need to adjust the channels.