Windshield Wiper arm will not move

My "left" windshield wiper arm will not move when I turn them on. The right arm moves, but the left arm stays stationary. I have examined the left arm to find that it is loose and flimsy. What will I need to fix this? I heard somewhere about a motor?

My "left" windshield wiper arm will not move when I turn them on. The right arm moves, but the left arm stays stationary. I have examined the left arm to find that it is loose and flimsy. What will I need to fix this? I heard somewhere about a motor?

The windshield wiper motor drives both arms, and therefore it sounds like the linkage from the motor to the L/H arm has come loose. The linkage is held on by a spring clip, and this may have come off.
Raise the hood and look at the lower part of the wiper arm assembly, and see if the linkage arm is attached.