Wiper Will Not Shut Off
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1990 GMC Vandura Special, 1990 GMC Vandura, 1990 GMC Rally Camper Special, 1990 GMC Rally, and 1990 GMC Magnavan. However, it is still accessible from the selected car via links, so may be relevant.
Disconnect wiring from terminals No. 3 and 4. See Figure . If motor stops, replace park switch assembly. If motor still runs, remove wires from terminals No. 17, 18 and 19. Connect a 12-volt lead to terminal No. 19 only. If motor does not run, it indicates a ground in wires from wiper motor to terminals No. 17 or 18 to dash switch. If motor runs, check for internal ground in high or low brushes.