Just did mine today on a D3. I had the same issue with blocked washer jets. For info the headlight jets were fine. This is because those pumps are higher than the windscreen jets on the washer bottle.
Anyway the filter was clogged with white gunk - a quick clean and all is as new - washer working perfectly. I will try to upload some photos - it is a fairly easy job when the wheel is removed. Did mine at the same time as changing to winter tyres so even less of a faff.
Here is the job:
You need to pull the top of the felt wheel liner away:
Then you can see the two pump assemblies :
The bottom pump is for the screen jets. You just pull/lever the pump upwards (can disconnect the electrics or not - I did just so I didnt break them but there should be enough wiggle to leave them be). The pump comes away and leaves behind a rubber grommet under which the filter is attached. Mine was full of snot / white / clear algae.
A quick clean:
Then all back together in reverse and jets are now back to being jet powered !
