The rear wiper may stop working. This could be due to a rear wiper motor that has failed requiring replacement.Google+
Car Problem Reports
Ford Explorer Sport Trac Replace Rear Wiper Motor if Rear Wiper Blade is Not Working
Ford Explorer Sport Trac Problem
Model Year Affected: 2002
Visitor, 2002 Ford Explorer Sport Trac, 77,000 mi
Rear wiper is not working. I can hear the motor running, but the wiper arm will not move. It is not getting stuck, it just will not move. It will not rotate even with the rear wiper arm taken off.