remove switch and (with help of wiring diagram) identify the two wires which go to the motor and put 12 volts across them (i used a battery charger to do this recently). By swapping the polarity of the temporary feed you should be able to get the window to raise / lower if the mechanism & motor are OK. If that checks out, and the feed to the switch is ok (again refer to wiring diagram and check with meter or bulb), then the most likely cause is the switch. A well know auction site is your friend:) (or depending on the type of switch you may be able to dismantle it and clean the contacts)
stevewes, August 2008
