The electric wiper motor is a permanent magnet, rotary electric motor. A worn gear machined on the armature shafts drives the output shafts and gear through an idler gear and shaft. The output shaft operates the output arm, which is connected to the wiper linkage. as the electric motor revolves the output arm, the linkage is forced to move in a back and forth motion. the speed of the electric motor is controlled by resistors, located on or in the control switch, and connected to the wiper motor electrical windings. the control switch directs the current through certain circuits of the wiper motor, as the driver desires.