Check fuses 41 and 60 in the fusebox behind the Glove Box...these two guys feed to the Body Control Unit....
On the right of the schematics is the two switch packs for the Left and Right rear doors, the two motors (Left & Right) and also the safety antitrap sensors....
When you toggle one of the switches, this signal goes to the BCUto tell it to open/close the window, the BCU then checks the antitrap sensor isn't sensing a blockage and then supplies power to the motor....
Check the fuses, and if they are good, time to check you get power to the motor (this will mean pulling the door card, or disconnecting the connection to the door and metering across the two wires to the motor.
If you have power - motor is fecked
If no power - time to check the switches....but seeing as though BOTH switches don't activate the window - it is unlikely to be that.
My money is on dirty door connections or a duff motor.