[Kizza]

Have you checked that the dual pump is working and that the lines are not blocked (switch the lines over on the pump and test if it works the other way). If so Its probably the wiper stalk contact that have dislodged (they have little locating pins that break off) and so contact isn't made.
You can take the wiper stalk apart, clean the contacts and glue them in place (also worth slightly bending them so they make good contact) - that fixed mine.

*If you buy a second hand stalk, this could easily have the same issue just so you are aware.