I'm looking for diagnostic and repair advice on the front wiper that quit. It is easily movable by hand, so I'm hoping the motor is ok and it might be a little loose nut...

 

if that has the 1 wiper blade style...try removing the black plastic cover that covers the piston ( lower part of the wiper arm. and lubricate the piston first before doing anything. ive seen screws come loose also.

 

Yes, it is the single wiper style. I removed the piston cover, and see that the piston still moves freely. I don't see how to remove the rest of the cover, as the piston passes through it, not under it. So I can't see where the cam has come detached. Does the whole assembly come off as a single piece? How shall I proceed?