windshield wiper arm

How does this arm on the driver side come off? It seems to be stripped motor is turning but arm is not. any help would be great

theres a black plug that is covering the bolt that holds the arm on. Just pop out the plug with a screwdriver then undo the bolt... Tip the arm in the up position then jiggle it side to side and it should snap free.

Mine did exact same thing when i changed my blades, do like livid said and remove the arm. Inspect the shaft make sure its ok. Then just turn on your wiper youll see the shaft turning side to side if not sumthin is wrong. My was just loose, the arm is a little tuff to seat down so when u put the arm back on, take your palm and just give it a good tap, not a hard tap, make sure u tighten the bolt down good, do not strip it! Then u outta be all set! Peace