Rear window washer
 

Not working, in fact it never did. Where is the motor for it?

There are 2 pumps (front & rear), both built into the washer fluid tank.

If you press the button (for the rear) and you can hear the pump then check the line at the back that connects to the wiper. If not, you can check the fuse panel.

you might be low on washer fluid. When low on fluid only front washer will work.