one of the blades does not move. I had tightened the wiper motor nut and it worked for a while then stopped. I tightened the nut again and it has not helped. I see the motor working but the blade does not move
windshield wiper not working on 2001 Hyundai Sonata
Chances are, the wiper spindle and/or wiper arm socket are stripped. You'll have to check them both and replace whats needed.