My little boy, JJ, decided to help daddy with his other wagon, he lifted the wiper up so he could clean behind it (I wasn't there at the time) - and it locked! I found it this weekend and have not been able to get it back down onto the windshield. I searched a lot here on the forum but came up with plenty of advice on how to remove the arm, but nothing about the arm being stuck in the open position.

Thanks all !