Wiper Inoperative, (All Modes)
- Check motor center terminal voltage with ignition "ON". With no voltage, check fuse or open wire between fuse block and wiper.
- With voltage, check problem in harness, wiper switch or motor. Set wiper switch to "LO", connect jumpers on motor grounding terminals "1" & "6" (see Fig 1). With ignition "ON", if wiper fails, problem is in wiper unit, proceed to step No. 3. If wiper operates, disconnect jumper from terminal "1", if wiper stops, trouble is in harness or switch. If wiper continues, disconnect jumper from terminal "6", if wiper stops, trouble is in harness or switch. If wiper now operates, and original problem was an inoperative motor, check for loose motor and/or wiper switch ground.
- Determine if problem is in gearbox relay, motor and/or pulse relay. With motor wiring connected, ignition "ON" and wiper in "LO", connect test lamp between BLACK-PINK lead and ground. If lamp fails, gearbox relay is defective. If lamp lights, check motor section and pulse relay. Remove washer pump cover, reinstall wiring. Disconnect BLACK (cotton braid) lead from override switch terminal and connect it to ground. With ignition "ON", wiper in "LO", if wiper fails, problem is in motor gearbox, visually inspect gearbox. If wiper runs, check lead connections to pulse relay, if good, problem is in pulse relay.
Courtesy of GENERAL MOTORS COMPANY