If at any time plain water was used in the reservoir slime occurs and this plugs everything up. In this case the tank has to be removed and the pump, fluid level sensor and hoses have to be cleaned. I had this when I got my car.
Try removing the lines from the nozzles and pump fluid through them.
The nozzles can be cleaned by blowing air through them.
The fluid jet can be adjusted with a paper clip in the hole, the nozzle is a ball and can be removed by snapping open the nozzle body.