The first thing I would check is to make sure the electrical connectors to your wiper motor are in good shape and making a good connection.I went through this last summer on one of my burbs.More than likely though it is the "control module"located under the steering column.If you take it off and open it up chances are good that you will see a small burn spot on the circuit board(although not always).Best bet is to search the boneyards or hit your friendly GM dealer.I can`t recall off hand what the price is,between 50 and 80 bucks up here in Canada.Probably cheaper where you live.It is the easiest part to change and more than likely the culprit,but if that doesn`t cure the problem then you might have to dig into the column and change the switch in there.
