As the single wiper arm moves across the windshield it is suppose to move up and down to reflect the contours of the windshiled. However, my wiper arm no longer moves up and down as it moves across the windshiled. Can someone tell me what might be wrong and how much it might cost to fix. Thanks

 

you might just need to grease the shaft the arm rides up and down on. you snap off the two covers and you can see the mecanism underneath. there's a good post on this with pictures somewhere on this site. hope this helps