K 2500 Truck 4WD V8-379 6.2L DSL VIN C FI (1989)
Wiper Switch: Testing and Inspection
Wiper Will Not Shutoff
Front wiper switch continuity test
Disconnect electrical connector from wiper motor, Fig. 19.
Ground terminal 5, connect jumper cable between terminals 2 and 3 and apply battery voltage to terminal 1.
If wipers continue to run, replace wiper motor. If wipers stop and park, replace wiper switch.