[gr8fl4porsche]

I had the same issue. Grabbed a gallon of Rain-X windshield washer fluid from Walmart when I was doing an oil change on the Yukon.

Wipers and washers were unusable.

I flushed the washer tank with a garden hose for 5 minutes.
Emptied tank with washer button.
Added 1 gallon of 50/50 solution of water and 99% isopropyl alcohol.
Emptied tank with washer button.
Cleaned windshield and wipers with ISO.
Added 1/2 gallon of straight ISO and ran half of it through the system.
Added 1/2 gallon of washer fluid to the remaining ISO in the tank and ran all of it through system.
I used the front and rear washers - alternating to let the pumps cool.

Now all is good.