Might also be worth syphoning out the contents of the screen wash tank, after a few years a lodge of sludge can build up at the bottom restricting flow.
Then replace with new screenwash and it should be better.
I had this problem once with an opel corsa. I think the previous owner had been using plain water,not screen wash. The water was like chicken soup with algae growing in it. I siphoned it out . The corsa has a filter in the bottom of the tank that stops crud getting into the pump and pipes. This was clogged. I flushed it out with a garden hose and a bit of careful poking with some stiff wire. Problem solved. Jets much stronger. I dont know the arrangment on your jazz.
Alternatively You may find the pipe to the jet has an accessible connection joint further down the line nearer the washer bottle. If you disconnect this and blow hard down the pipe it might clear the blocked jet. Only use lung power. An air line might be too much pressure. It might help dislodge a blockage if you alternately suck and blow on the pipe. Problem here is you dont really want to get any screenwash into your mouth. It can contain all sorts of nasties , or contain 'bitrex' which makes it very bitter and unpalatable. . (I have a 'peach scented' summer screen wash that does smell good enough to drink.
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I know its not relevant this time of year , but my Yaris was quite prone to the jets freezing. Not the fluid, which I have at minus 20 in the winter. ., I think the design allowed ice melt to gather externally which seeps into the jets and freezes. .
