The first thing I would do is take a rubber hammer and hit the door just below the trim panel while holding the switch in the down position and see if it starts to work. I have had a number of these with stuck motors and some times they begin to work after tapping the door. If it starts to work you will need a window lift motor.
There hasn't been many issues with the power windows in these van's, so give that a try to see if it starts to work. There is realy nothing else I can suggest without pulling the trim panel off, so let me know if it starts to work, Thanks!