The rear wiper is controlled by an input from the rear wiper/washer switch which is located in the instrument panel. When the WIPER portion of the switch is pushed into it's detent the rear wipers are turned on, a voltage signal from the fuse block is applied through the wiper washer switch to the rear wiper motor to command it ON.

When the WASHER portion of the switch is pressed the rear washers are turned on, the switch has a momentary contact in the washer position and will continue to spray as long as the switch is being pressed and will stop when it is released.