1989 Pontiac Sunbird windshield wipers

It could be the control board on the wiper motor or the switch. Do you have a multimeter to do some trouble shooting?

I posted how to test the switch when testing the switch make sure the key is in the run position. Also when they say make sure you do a continuity test before checking the switch they are talking about unplugging both the wiper motor and the wiper switch and with the key off make sure you have a connection from each terminal to the opposite connector. Just match the colors up when checking for a connection from the wiper motor connection to the wiper switch connector like orange and orange etc. Set the meter to the lowest ohms scale you have to test that. Let me know what you find. Also don't push your terminal tips on the meter into the terminals of the connectors to hold them in place or you will create a new problem a terminal tightness issue.