Mine were not working since I got the car. I could hear them trying but never saw fluid. Then one day I just happen to be looking into the cowl and could see it squirting in there. Now that winter is upon us I wanted them fixed. So I pulled off the cowl plastics (easy) and the wipers. Once in I could see, I guess the drivers side wiper hose connected to the pass side wiper under the cowl plastics, it broke at the pass side connection, so a T and a little new hose I was good to go again.
I didn't have fluid working on my 1993 Silverado either, new motor in the fluid holder and all if good there also.