How does the power window work in the front door of a 1997 Mercury Grand Marquis?

There is an electric motor that drives a geared pulley which is attached to a sliding bracket attached to the window. Most of the time the cable jumps off due to dry or binding window/channel. There are rubber spacers in the gear attached to the motor that deteriate in the heat and crumble. You can buy a new gear kit and replace it.