[effpee]

Try pushing a thin bit of wire in the jet to see if that clears it, then put some vinegar in the screen wash bottle to dissolve any lime in the system.
when the system is clear drain the screen wash tank and fill with distilled water and screen wash.
Never use tap water as it is contaminated.
I did this to my toilet to stop it dripping down in to the bowl It worked over night in that situation.