The Windshield Water Pump on a 1999 Pathfinder is located at the bottom of the Windshield reservoir.
To get at the pump,first remove the front right tire(Passenger Side).
Then, remove the black plastic wheel guard that should be marked with FR(Front Right). You only need to remove this one guard. There are other wheel guards but they do not have to be removed.
Once this guard is removed you will see the Washer Pump.
You should also notice that there are two pumps. One is for the rear window(usually) the pump on left and the front washer(one on left) The rear washer pump usually will have a clear hose attached while the front will have a black hose.
When you purchase your new washer pump most likely it will come with one hose outlet while the old one will have two outlets. Make sure that the new washer pump kit has a tee junction in it so you can connect the two hoses.You have have to purchase 6 to 8 inches of black hose to connect the tee junction.
A little wiring is also required which is very easy. Just follow your kit instructions making sure you connect positive to positive and negative to negative. On my Pathfinder the negative wire was blue with a yellow strip. Postive was a blue wire with a black strip.
I how this information is helpful. The replacement part will cost $30.00 - 35.00 but you will save an average of $150.00 on labor if you were to have a garage do the replacement. The job should take you around 2 - 2 1/2 hours to complete.