Mike's Workshop Manuals: Service manuals for every vehicle
Home >> Jeep >> 1999 >> Grand Cherokee Laredo, 4.0 S, AWD >> Repair and Diagnosis >> Body & Frame >> Body, Cab Control Systems >> Body Control Computer - Tests >> Windshield Wiper/Washer System Symptom Tests >> Wipers Inoperative

Wipers Inoperative

  1. Replace wiper high/low relay in Power Distribution Center (PDC) with known good relay. If wipers operate correctly, replace wiper high/low relay. If wipers do not operate, go to next step.
  2. Replace wiper on/off relay in Power Distribution Center (PDC) with known good relay. If wipers operate correctly, replace wiper on/off relay. If wipers do not operate, go to next step.
  3. Turn ignition off. Disconnect wiper motor connector. Measure resistance between ground and terminal No. 4 (Black wire) on wiper motor harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, repair open Black wire.
  4. Remove wiper on/off relay. Remove junction block circuit breaker No. 1. Connect jumper wire between ground and fused ignition switch output on circuit breaker No. 1 socket. Using ohmmeter, measure resistance between ground and terminal No. 86 (Dark Blue wire) on wiper on/off relay socket. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, repair open Dark Blue wire.
  5. Turn ignition off. Ensure both wiper relays are removed. Using ohmmeter, measure resistance of Yellow/Dark Green wire between terminal No. 30 on wiper on/off relay socket and terminal No. 30 on wiper high/low relay socket . If resistance is less than 10 ohms, go to next step. If resistance is 10 ohms or greater, repair open Yellow/Dark Green wire.
  6. Ensure wiper on/off relay and junction block No. 1 circuit breaker are disconnected. Measure resistance between ground and terminal No. 86 (fused ignition switch output circuit) on wiper on/off relay socket. If resistance is less than 10 ohms, repair fused ignition switch output circuit for short to ground. If resistance is greater than 10 ohms, go to next step.
  7. Disconnect Body Control Module (BCM) C1 connector. Turn ignition on. Using voltmeter, measure voltage between ground and terminal No. 22 (Red/Violet wire) on BCM C1 harness connector. If voltage is greater than one volt, repair Red/Violet wire for short to voltage. If voltage is one volt or less, go to next step.
  8. Turn ignition off. Ensure both wiper relays are disconnected. Using ohmmeter, measure resistance between ground and terminal No. 30 (Yellow/Dark Green wire) on wiper on/off relay socket. If resistance is less than 10 ohms, repair Yellow/Dark Green wire for short to ground. If resistance is 10 ohms or greater, go to next step.
  9. Measure resistance between ground and terminal No. 87A (Brown/White wire) on wiper high/low relay socket. If resistance is less than 10 ohms, repair Brown/White wire for short to ground. If resistance is 10 ohms or greater, go to next step.
  10. Ensure BCM C1 connector is disconnected. Connect jumper wire between ground and terminal No. 22 (Red/Violet wire) on BCM C1 harness connector. Using ohmmeter, measure resistance between ground and terminal No. 85 on wiper on/off relay socket. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, repair open Red/Violet wire.
  11. Ensure ignition is off. Ensure junction block C2 connector is disconnected. Remove junction block circuit breaker No. 1. Using ohmmeter, measure resistance between terminals No. 8 and 9 on junction block C1 harness connector and fused B+ terminal on circuit breaker No. 1 socket. If resistance is less than 5 ohms for both circuits, go to next step. If resistance is 5 ohms or greater for either circuit, replace junction block.
  12. Ensure all connectors and components are connected. Disconnect wiper motor connector. Turn wiper switch to LO position. Using voltmeter, measure and record voltage between ground and terminal No. 5 (Brown/White wire) on wiper motor connector. Turn wiper switch to HIGH position. Using voltmeter, measure and record voltage between ground and terminal No. 6 (Red/Yellow wire) on wiper motor connector. If voltage for both circuits is greater than 10 volts, replace wiper motor. If voltage is 10 volts or less or either circuit, go to next step.
  13. Turn wiper switch to LO position. Using scan tool, read wiper mode switch voltage. If voltage is about .82 volts, replace BCM. If voltage is not about .82 volts, test is complete.
scientia non olet · About Mike's Workshop Manuals