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HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 173 (WIPER SYSTEM AND WASHER SYSTEM)SYSTEM TESTSTEST F: WIPERS INOPERATIVE (ONE OR MORE MODES)
1999 GMC Forward Control 5.7 R, Automatic

Test F: Wipers Inoperative (One Or More Modes)

1999 GMC Forward Control 5.7 R, AutomaticSECTION Test F: Wipers Inoperative (One Or More Modes)
WARNING: This page is about a different car, the 2002 Buick Regal and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: The numbers below refer to the step numbers on the diagnostic table:
  1. 8  - This step tests for continuity through the 24K ohms resistor in the windshield wiper/washer switch. The connector behind the instrument panel knee bolster is suitable for performing this step.
  2. 9  - This step tests for continuity through the delay resistors in the windshield wiper/washer switch. The measured resistance will change in sequence from high to low as the delay speed is increased. The connector behind the instrument panel knee bolster is suitable for performing this step.
  1. If wiper/washer system description and operation has been reviewed and preliminary inspection has been performed, go to next step. If wiper/washer system description and operation has not been reviewed and preliminary inspection has not been performed, go to DESCRIPTION & OPERATION  and DIAGNOSTIC STARTING POINT  under TROUBLESHOOTING.
  2. Turn ignition switch to ON position. Turn windshield wiper/washer switch through all switch positions. If wipers do not operate properly, go to next step. If wipers operate properly, check for intermittent or poor connections. Repair as necessary.
  3. Do the windshield wipers operate in the high speed mode? If so, go to step  5 . If not, go to next step.
  4. Disconnect the windshield wiper motor connector. Connect a test light from the windshield wiper motor high speed circuit terminal to ground. Turn the ignition ON. Operate the windshield wiper/washer switch to the high speed position. Does the test light illuminate? If so, go to step  16 . If not, go to step  10 .
  5. Disconnect the windshield wiper motor connector. Connect a test light from the windshield wiper motor accessory voltage supply circuit (Yellow wire) terminal to ground. Turn the ignition ON. Does the test light illuminate? If so, go to next step. If not, go to step  11 .
  6. Connect a test light from the windshield wiper switch signal 2 circuit (Dark Green wire) terminal to ground. Press the windshield washer switch. Does the test light illuminate? If so, go to next step. If not, go to step  12 .
  7. Connect a test light from the windshield wiper switch signal 1 circuit (Gray wire) terminal to ground. Operate the windshield wiper/washer switch to the following positions:
    • MIST
    • LO
    • HI
    Does the test light illuminate in the listed switch positions? If so, go to next step. If not, go to step  13 .
  8. Disconnect the windshield wiper/washer switch connector. Measure the resistance through the windshield wiper/washer switch from the signal 2 (Dark Green wire) circuit terminal to the accessory voltage supply circuit (Yellow wire) terminal in the switch side connector. Operate the windshield wiper/washer switch to the following positions:
    • MIST
    • INT
    • LO
    • HI
    Is the resistance at or near 24K ohms in all the listed switch positions? If so, go to next step. If not, go to step  14 .
  9. Measure the resistance through the windshield wiper/washer switch from the signal 1 (Gray wire) circuit terminal to the accessory voltage supply circuit (Yellow wire) terminal in the switch side connector. Operate the windshield wiper/washer switch through all of the delay positions. Does the resistance remain within 38K-690K ohms from high to low as the delay speed is increased? If so, go to step  16 . If not, go to step  14 .
  10. Test the windshield wiper motor high speed circuit for an open or high resistance. Did you find and correct the condition? If so, go to step  18 . If not, go to step  14 .
  11. Repair the windshield wiper motor accessory voltage supply circuit (Yellow wire) for an open or high resistance. After repairs are complete, go to step  18 .
  12. Test the windshield wiper switch signal 2 circuit (Dark Green wire) for an open or short to ground. Did you find and correct the condition? If so, go to step  18 . If not, go to step  14 .
  13. Test the windshield wiper switch signal 1 circuit (Gray wire) for an open or short to ground. Did you find and correct the condition? If so, go to step  18 . If not, go to step  14 .
  14. Inspect for poor connections at the windshield wiper/washer switch. Did you find and correct the condition? If so, go to step  18 . If not, go to step  15 .
  15. Replace the windshield wiper/washer switch. See WIPER/WASHER SWITCH  under REMOVAL & INSTALLATION. After repairs are complete, go to step  18 .
  16. Inspect for poor connections at the windshield wiper motor. Did you find and correct the condition? If so, go to step  18 . If not, go to next step.
  17. Replace the windshield wiper motor cover. See WIPER MOTOR COVER (CIRCUIT BOARD)  under REMOVAL & INSTALLATION. After repairs are complete, go to step  18 .
  18. Operate system to verify fault no longer exists. If fault still exists, go to step  3 .
RENDER: 1.0x

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