Hi there hope i can be of assistance,
Ok if you have replaced the fuse, you now need to check the power supply to the motor.
You should have 12v, when the rear wiper is switched on. If you do, then the motor has failed.
If you have a reduced voltage, i.e les than 11v, then youll most loiekly have a wiring problem. The most common place for this is where the wiring enters the boots. Due to its location the wiring rubs/chafs together until it eventually stops the component working.