This one is probably better for all you LHD fortwo owners out there.
The original smarts (Mk 1 to 3) had washer jets mounted on the top wiper arm and didn't just spray the wipers like the current ones (although the new location does stop water from freezing in the pipes).
However, the plumbing still exists on fortwos to retrofit the old style wipers. This mod will allow a more even spray of fluid onto the screen.
You will need one Jet wiper arm SQ000 1566 V002 and...
First, the head of the washer jet clips around the dot on the top (nearside) wiper arm. (see picture 1).
The plastic clip on the tubing clips on the spring under the lower arm. (see picture 2)
You may also need a discreet black cable tie to keep the centre section of tubing in place.
Next lift the cap at the base of the nearside wiper arm, to show a small stud and hole. The hole provides the channel for the washer fluid; the connector fits on the hole (by the bit by the green arrow) and is located on to the stud by the recess (blue arrow). It takes quite a bit of force to squeeze the connector in, so if necessary use a screwdriver to push it in using the wiper arm above for leverage.
Plug in the pipe; there's even a notch in the cap for the pipe to pass through when you fold it back down. (picture 1)
Next the tricky bit: below the hole where the connector is inserted is another (elbowed) connector.
You'll need to fit one end of the washer tubing onto this connector. TIP: soften the tubing in some hot water first.
I managed to do this through the nearside service grille. You just need to reach towards the bottom of the wiper arm and feel around the mechanism until you find it. If you can't do it this way then it's going to have to be a front-off job. (picture 2)
Once on, run the pipe along a suitable route to the splicing point (see picture)
Now to plumb this new line into the washer pump. Under the nearside service grille you'll find a black rubber pipe on your right. If you're greedy and want to have both jets working, cut the line and use a tee to splice into it. (The clear line is the new one that leads to the new jet) One worry was that I'd lose pressure by doing this, but in the there wasn't a difference.