If the wipers work slowly, check the battery's condition and charge. If the battery is fine, remove the wiper motor and inspect the wiper arms' movement by hand for binding linkage or pivots. Lubricate or repair the linkage if necessary and reinstall the wiper motor. If the wipers still operate slowly, inspect for loose or corroded connections, especially the ground connection. If all connections seem fine, consider replacing the motor. In case the wipers fail to operate when activated, check the fuse, and if it's okay, try connecting a jumper wire between the wiper motor's ground terminal and ground to test. If the motor works with the jumper, repair the ground connection; otherwise, turn the wiper switch to the HI position and check for voltage at the motor. If there's voltage at the connector, remove the motor and test it off the vehicle using fused jumper wires from the battery. If the motor works, check for binding linkage, and if it still doesn't work, replace it. If there's no voltage to the motor, check for voltage at the wiper control relays. If there's voltage at the relays but none at the motor, have the switch tested; if the switch is okay, the wiper control relay may be faulty. If the interval (delay) function is not working, examine the continuity of all the wiring between the switch and wiper control module. For wipers that stop at the current position when turned off (fail to park), check for voltage at the park feed wire of the wiper motor connector when the switch is OFF but the ignition is ON. If there's no voltage, check for an open circuit between the wiper motor and the fuse panel. For replacement of the front wipers, start by disconnecting the negative battery cable, then remove the wiper arm nuts, mark their positions, and take off the wiper arms. Remove the cowl grille, followed by the wiper motor/linkage mounting bolts. Finally, remove the assembly and unbolt the motor from the linkage. The rear wiper replacement involves disconnecting the negative battery cable, marking the wiper arm positions on the liftgate glass, removing the wiper arm cover and nut, and the bezel carefully to avoid scratching the liftgate paint. Proceed by removing the upper and lower liftgate interior trim panels, disconnecting the electrical connector at the rear wiper motor, and removing the two mounting bolts.
Posted by GMPartsGiant Specialist 
