On vehicles with intermittent windshield wipers, the wiper motor circuit board may fail and cause the wipers to stop working at times. Replacing the circuit board should resolve the issue. Some vehicles were recalled for this problem and some were not. You will need to check with your local dealer to find out if a specific vehicle was included.Google+
Car Problem Reports
Chevrolet S10 Failed Wiper Motor Circuit Board May Cause Intermittent Wipers to Stop Working
Chevrolet S10 Problem
Average Mileage: 62,750 mi (10,000 mi - 150,000 mi)
Visitor, 1998 Chevrolet S10, 78,000 mi
My wipers don't like to work when it rains, but work fine otherwise. Not a good situation...and gets frustrating...
Visitor, 1996 Chevrolet S10, 150,000 mi
Wipers operated sporadically. Sometimes would not shut off without shutting off the ignition. A new circuit board cured the problems.
waper only work when that wont to work.
Visitor, 1998 Chevrolet S10
wipers only work when they want too. Replaced the ciricut board but intermittent only works when it wants too
Visitor, 1997 Chevrolet S10, 94,000 mi
I have been dealing with this problem for years but it was not a big deal in Southern California as it does not rain that often.