I just had mine out and really there really isn't anything to service. I added some grease behind the rubber gasket and took the plastic cover off and put a little bit of grease
on the white plastic wheel. You can also remove the wiper arm transmission and use some white lithium grease on the end piviots. I only did all this cause my wiper arms did not park. Now that they are sitting right everything is good. Try rolling down the window and with the keys in the ingnition turn your wiper switch and see if there is any thing visually happening.
Yeah well coming home from kirbans open house this year I had to use mine
and the wipers suck on these cars. Mostly since there were wipers on the car that havend been replaced in 2 yrs. GNTTYPE has an article on there about fixing the wipers so they Park. Article sucks without pictures. So best to play around with taking everything apart and figuring it out yourself.