I had one go on me for about a month, and then one day I just pulled up harder than you would to close the window, and then pushed down, again, harder that you would to open the window. Did this about 5-6 times, and the switch began working again. That was a year ago, and still works.

Of course, the entire switch assembly on my car had also been replace twice under warranty.

Common failure, but some have had luck with electronic parts cleaner. I guess the contacts in each individual switch collect stuff that gets in the way, and causes the failure.

BB