Power window switches are a common problem and are pretty easy to fix by yourself for virtually nothing.
Remove the switch panel from the door- unplug the switch and use a tiny screwdriver to release the switch from its fingers in the plate.
Open up the switch by prying around its edges- you'll see the little tabs that hold it together. There are two springs, two tiny ball bearings, and two see-saw type contact in there. The bottom part of the switch has the contacts on it- they're silver, and they get burnt and pitted really bad. BTW don't lose the parts when the switch pops open! Do this over a pan or a surface where things won't roll away.
File the contact points down flat with a fine file- even a nail file will do it, the silver is soft. File until the pits are gone and the contact is smooth. If you have a little dielectric grease, it would be good to coat the contacts and balls/springs with it. Line everything back up and snap the switch back together.
Plug it in and your windows ought to work like new.
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Rob Bareiss, New London CT ::: '87 244DL/M47- 220K, 87 244DL- 230K, 88 744GLE- 198K, 91 244 180K, 88 244GL 145K