I would unplug the connector to the wiper motor and replace the fuse, if its the motor causing overload then the fuse should be ok without the motor on the circuit, If it doesn't blow connect up either a test light or volt meter and turn the wipers on, this in theory shouldn't blow as the motor isnt connected, If it does then it means that even with a low current draw the wires cant handle the load which would indicate a short circuit in the loom.
