Have you had any luck with this? I am trying to sort the same problem on my 99 espace. I disconnected the pipe where it joins on to the rear wiper but no fluid comes out so it is not getting that far. I can hear the pump running.
A little tip here, on the inner wing near the near the washer bottle filler you can access the two pipes to the front and rear, i got the wife to opperate the rear washer whilst i squeezed the pipe and the pipe gets hard
so it is getting that far. I suspect the pipe is blocked or trapped somewhere.
The renault drawing i have shows the pipe running through the bulkhead, and following the top of the sill inside the car then over the rear inner arch, somwhere near the end of the rear arch it runs up to the roof area and through the rubber boot in to the tailgate. Hope this helps somebody.
PS the front and rear washers use the same pump, according to my renault drawing, and the headlight washer is on a seperate pump. The pipe is all in one section apart from one joint near the bulkhead somewhere.
I will update if i make any progress.