The crank has probably come loose.
Lift hood. Pull up plastic cowl cover on passenger side.
There is an oval rubber plug.Remove it.
You should be able to see an aluminum crank just laying there. It has a plastic cup on each end. it should snap back on to the end that comes from the motor. You can move the wipers by hand to get it to the right positiion.
The plastic ball will sometimes break and in that case get an arm from the junk yard. You'll need a 14mm socket to remove the wiper arm and a 10mm to remove the center pivot that connects the two arms. The arms are different lengths, so you'll have to get the one that matches the busted unit.
a fairly common problem especially due to heavy snow is for the spindle nut at the base of the wiper arm to be a little loose. this allos the motor to turn the spindles but the arms to not move. but probably not likely for both to be lose at the same time. but still worth checking.