What needs replaced if the window goes down but not up on my 200sx?

If the window goes down but not up on your 200sx, the most likely cause is a faulty window regulator. The window regulator is the mechanism that raises and lowers the car window. It is typically located in the door panel. To replace the window regulator, you will need to remove the door panel and disconnect the window glass from the regulator. You will then need to mount the new window regulator and reconnect the window glass.