Had a very similar problem with my washer jets recently. Lack of pressure. Took everything apart cleaned and refitted, no improvement. Replaced the washer jet assemblies and now they wash as good as a new car, turns out that the years of use, cleaning and adjusting had worn away the jets. Not sure if you have the first generation square washers or the second generation large oval type. My ones are the later (heated) and picked up replacement A4 ones made in china. They are a perfect fit and almost perfect copy except they have identified them the wrong way around. Just make sure the outer jet points to the outside in each case. If you have flow then the pump is working, be prepared to replace some of the plastic tubing, I had to replace a section between the two jets that had become very brittle and fell apart as I was taking out the old jets.