I experienced this yesterday, and this is how I fixed the isse, though Haynes solution may vary from mine..
Problem: window wiper slows down/ stops.. Since you need the wiper, this is a -need to do fix-
Tools/ parts: the good part is, your granny can fix this. You need an umbraco, a flat screwdriver, fat/ grease (I used urathan fat) and that's it.
Solution: if you wipermotor isn't killed, it just needs to be lubed up again.
1. Remove the wiper blade and the arm attached to it, (have avaliable some paper or something soft to use between you window and the metalpart on the wiper which now leans towards your window.
2. Bend the wiperarm to the upwards position and remove the first middle plastic cover to uncover the hex screw. See picture.
3. Remove the rest of the wiper (help with the flat screwdriver, this makes it easier) after removing the hex screw.
4. Remove the main plastic cover to uncover its mechanism, see picture. Lube alle moving parts and the pendle underneith. Use a water proof fat/ lube, I used Urethan grease..
5. Reverse step 1-4
