Look between the battery & headlight. The cap should be labeled.
Mounted on the bottom of the washer fluid reservoir.
According to the 2002 Ford Explorer Owner Guide the washer fluid for the rear liftgate is supplied by the same washer fluid reservoir as the windshield ( located in your engine compartment )
On firewall directly in front of driver.
I believe you have to remove the battery, battery tray and then the washer fluid reservoir, now you can remove the pump from the reservoir.
Your windshield washer fluid reservoir is low.
On a 2002 Ford Ranger : The reservoir would be in the engine compartment There are reservoirs for brake fluid , windshield washer fluid , power steering fluid , engine coolant , etcetera
Follow the hoses from the washer outlet spray heads backward to the washer reservoir.
Uses front reservoir
Follow the hoses from the washer outlet spray heads backward to the washer reservoir.
should be the same reservoir as the front windshield wipers
According to the 2002 Mercury Mountaineer Owner Guide :The washer fluid for the rear liftgate is supplied by the same reservoir as thewindshield ( located in the engine compartment )
Antifreeze is in engine compartment on right side between brake fluid and washer fluid reservoir