Have a look at the attached diagram.

When the wiper switch is moved to position 1 (slow), 12V is fed from the fuse to the switch (terminal 54), then via switch terminal 53 to the wiper motor (green wire in diagram)

When the motor is switched to position 2 (fast), 12V is fed from the fuse to the switch (terminal 54), then via switch terminal 53B to the wiper motor (red wire in diagram).

The switch terminal numbers are marked on the switch if you remove the connectors.