How do I fill the rear window washer fluid?

The washer fluid might be empty. Have you tried adding some?

Turkey baster or unplug hose under fill tank and drain.

Probably broken fluid hose. Replace same.

check for break in the wiring at your trunk/boot.

Yes it does and the washer fluid reservoir under the hood is for both the front and rear. The following is a diagram of the washer pump and hoses so you can check for operation or leaks.

http://www.nissanmurano.org/forums/attachments/problems/15059d1233342517-rear-washer-fluid-not-squirting-washer-motor.jpg

Just one.Check the lines and the pump at reservoir,

its more than likely the bulb has gone, it will if you leave it on for long periods of time, can be a led on some dashes and they can last longer than bulbs but sometimes they dont.

YOU CAN GO DEALERSHIP OR THE SALVAGE YARD PROBABLY HAVE A WASHER FLUID TANK AND HOSES IN GOOD SHAPE.

check in the cargo area of the vehicle, there should be an access panel on either the right or left panel in back. if it has a separate reservoir that's the most probable location
hope this helps

there shouldn't be any rear washer fluid reserve for you back window there's only one reserve and that's under the hood which controls the front and back. but also you can call your local dealer and ask them.