I did not know in the Scenic but in my Clio II 2001 I did not walk both, I did not throw in any. I disassembled and took the water storage where I was put to pressure the motor and found that I was flooded and recontra-oxidized. After several minutes of turning it with an already force of WD40, it was normally turning, I recommend trying it directly to the battery until it recovers revolutions. The engine itself is nothing more than a 12V CC (continuous current) motor, which invests the direction of turn according to polarity, which gives water to send the water by one or another pipe. It has a plastic palettes at the tip of the motor that they make of mini water pump. Observe well which is which before assembling, so it is sending water where it corresponds. I hope I have helped something, greetings.