Here's on for people getting ready for the season. My wiper motor failed to operate for a while so had a peep at it yesterday. Most people would probably get a new one but I always like to know why a component stops working. First check is it receiving power, in my case yes, then I disconnected and removed it, then unscrewed back plastic cover inside is the motor winding and two spring mounted carbon brushes, I then cleaned the surfaces of brushes (be careful that you don't lose them as they are only held in by the spring pressure) I use baby wipes as they are oil and lint free. I reassembled and it worked fine.
Motors like these that are not used and are in damp conditions can and do fail and like mine generally just need a clean!
Just hope this saves someone splashing out on a new one!
Donal