* Broken regulator: The regulator is the mechanical part that connects the motor to the window. A broken regulator can prevent the window from going up even if the motor is working.
* Wiring issues: A short or broken wire could prevent the motor from receiving the signal to go up.
* Switch problem: The switch that controls the window might be faulty, only sending the signal to go down.
* Binding window: Something might be jamming the window from going up, such as debris or a malfunctioning track.
While the motor is a strong suspect, you should investigate these other potential problems before assuming it needs replacement.