Yeah, the one with the washer symbol turns on the wiper, and, when pushed further forward, into the momentary position, squirts the water out of the bag in the driver's side "storage" compartment. The one that holds the jack, tool kit, and anything else you might put in there. It does need wiper fluid in the bag. It's also prone to freezing up in really cold weather. If the bag has been empty for a long time, it takes a while for the washer fluid to go through the tubing and out.

Finally, the rear window must be all the way up for the wiper to work. If the limit switch that stops the rear window from going too far up is bad, the wiper will not work. If there's anything in the rear window's track, especially up at the top, the wiper will not function.

The rear door must be locked, as well. If the button in the back door isn't all the way down, the wiper will not function. It's supposed to go down, lock, when the rear window is actuated, but as the mechanism gets old and stiff, the button may not go down far enough to allow the wiper to function. You can try putting the back wind down, pushing the button down manually, then putting the window up.

The other button, labeled "UP", operates the rear window, both up and down.

Hope this is some small help...
I owned an 87 4Runner from 97 to 2020. I got REAL familiar with all those buttons.
Pat☺