Could be a number of things:I just tried to open the rear (tailgate) window in my 2001 Sequoia and it won't open. Tried both the keyless remote and the switch inside the vehicle. The window lock is not engaged. Any ideas?
window stuck to rubber seal - try using your hand to assist it when you attempt to lower it.
wiper not seated properly - I believe if it is not seated properly, it won't allow the window to open.
bad motor - this is fairly common...if you do a search, you might be able to find more info on this.