[hyundai_on_thames]

Symptom: Rear washer motor can be heard, but nothing comes out. If you try for long enough you'll find a damp patch at the back of the roof trim.

Solution: Prise the roof trim buttons loose then get fingers between trim and roof to pull trim down. Check the washer hose.

Mine had parted where you see that while plastic connector between the 2 sections of tube:

[AlanHo]

A similar thing happened on my i30 GD 3 years ago. In my case the rear hatch was leaking water. Being lazy I got the dealer to do it under warranty.

[Dazzler]

@hyundai_on_thames  Thanks for that!