2002 Rear Wiper Pump

My 2002 Ford Explorer rear wiper works great but when I go and push the fluid to come out it doesn't. Front windshield wiper and fluid works fine. I even refilled the fluid tank in the front, which according to the owners manuel works the front and back. Where is the rear wiper pump located ? and is it replaceable ? Or is the pump and the rear wiper motor one unit ? Help................

Not sure about the 2002, but I currently have a 1999 and, unlike my old 1992 Explorer, the 1999 uses just a single pump in the front for both the front and rear sprays. If you can hear the pump when you push the rear spray but get no spray I would guess you have a clog and/or a leak in the tubing that runs from the front pump to the rear wiper. If you cannot hear the pump when you push the rear spray than I would guess the rear spray switch is bad. I'd first check it to make sure it's working properly. Hope that helps.