When you open the doors the windows always slide down and when you close them it goes up. But if you're removing the battery and still need to access the car, the windows wont roll down and opening them is still possible, but closing the door isn't. So before disconnecting the battery, open your doors, disconnect the sucker and then the windows will always be slightly rolled down enough for the door to close well and not leave any space for insects or spiders coming inside.