non-functioning rear window wiper

It's probably the switch, motor or the wiring. It's common for things in the rear door to stop working because of a broken wire in the hinge area (from opening and closing the door). Try opening the rear door and see if it works, if it does, you probably have a bad wire harness. If the motor is seized, you can get it to temporarily work by hitting it with a hammer, you basically want to smack the motor. Closing the door "firmly" while trying to operate the motor can sometimes achieve the same thing. If all this fails, you'll need to diagnose the problem by checking the power and ground to the wiper motor.