Renault Megane H/B 1999 Model - Wiper Problem?

1999 Renault Megane H/Back. Problem with wipers, both back and front. Back wipers will not work - We have ascertained the back wiper motor is fine by connecting to a battery. Don't know why it won't work? Front Wipers - the front wipers will not pump water, again we know the motor is working but not pumping. The front wipers will work in the normal mode but if I pull the hand as if to spray water on the windscreen the wipers stall in mid-motion. All the fuses have been checked and nothing to do with that. Any ideas??