Wiper Operates (Hi Only)
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.
Turn ignition switch to ON position. Turn wiper switch to LO speed position. Leave wiring connected to wiper. Connect a jumper wire from terminal No. 18 to ground. See Figure . If wiper runs at low speed, problem is an open wire from wiper terminal No. 2 to wiper switch. If wiper is inoperative, repair wiper motor.