according to the wiring circuit, the motor receives constant 12v feed via blue wire (to keep gear spinning during wipe till its returned to "park" position), ground via black, and a switched 12v via light green wire (to trigger movement when gear in "park" position).
I would measure light green & black wire whilst switching wiper on off to check all the circuit & relay is actually working, sending a trigger voltage to the motor.
if the circuit is working ok, next is check the motors circuit is intact.
motor is usually still in Park position awaiting a trigger voltage from lt green to set it off. so measure the ohms between where the lt green & black wires would go on the motors connector and it should be intact.
if there's no reading then either the sliding contact on the spinning gear for the 12v trigger circuit is worn out (common) and/or the motor is worn/damaged.
the rivets holding the cover plate over the spindle gear can be grinded off to expose the sliding contacts and inspect their condition. you'll need to carefully drill & tap new holes to screw the cover back on.
here's when I disassembled the front wiper motor, rear motors the same procedure
https://www.micra.org.uk/threads/pollymobiles-rebuild.35251/page-116#post-701391