Rear window washer , water pouring into tailgate

[Atrax100]

I have a strange one. On the inside of the rear windscreen washer (under the interior carpet trim cover), there appears to be some sort of round cap or plug missing from the outlet chamber to the washer nozzles, that the rubber hose attaches to, allowing the washer fluid to just pour into the tailgate. It’s just an open round hole? Why it would not just be a solid, one piece plastic fitting eludes me. In any event I have to replace this in order for the fluid to get to the spray nozzles. Anyone have any clues on what this part is called? Do I have to replace the entire rear washer assembly? I'm clueless here.
Cheers.
Neil

[hoonk]

Here is a picture - the nozzle is a tube that runs through the center of the wiper motor shaft, hose connects inside the door. It sounds like you are describing a broken check valve in the nozzle (#7 or #2-3) -5444