2000 Tahoe rear hatch window won't open

I have a 2000 Chevrolet Tahoe that we can't open the rear hatch window with a key or by pressing the button.  Anyone know anything about this problem? The rear hatch opens fine, just the window doesn't open.

You will need to open the rear liftgate and remove the inside trim panel, then you can determine which part has failed, it could be the latch or the actuator cable.