The window regulator, located inside of the door panel, allows the window glass to roll up and down along the window track. It is used in both manual crank and power windows. If it is not functioning properly, the window may not roll up, down, or both. It may also move the window unevenly, or make a grinding noise while in motion.

Window regulators are generally built to last, and do not require scheduled maintenance. However, over long periods of time the mechanical components can corrode or wear down, and the regulator may need to be replaced.