Being that it does vent, then power is getting to the switch and through the switch.
However, it is a multi-pole switch. So, it may be getting only to one side.
From the switch it goes to a module back near the rear window. The module receives info from the switch and then tells the motor what to do.
There are sensors on the window that cause communication with the module as well. But,,, since your window is not going down past vent, I cannot see the sensors being the issue.
I would suggest to test near the module to see if power is getting through both sides of the switch and then go from there.