Window motor is a device installed inside the door panel behind the trim to raise or lower the window when the switch is pressed by you. After a longtime usage, the window motor has a high risk failing. If your window motor is worn, you may suffer a slow-moving window when you ask to raise it, and when you release the button, it stops instead of continuation. Or even worse, the window goes back to downside after you release the button. Anyway, either of them happens is not expected, and it is abnormal, so these are some hints showing your window motor is failing or broken at all. It is easy to change the window motor by yourself after you remove the door panel and you will find it easily. Before that, you have to own a brand new window motor, and you can definitely find a good one here. We offer you all BMW genuine window motor with an unbelievable cheap price.