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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 16 (Steering Column & Steering Column Switches) >> System Tests >> Test B: Horns Inoperative >> "U" Series

"U" Series

WARNING: This page does not describe the selected car, but rather 16 other vehicles, including the 2001 Pontiac Montana, 2001 Oldsmobile Silhouette, 2001 Oldsmobile Bravada, 2001 GMC Sonoma, and 2001 GMC Savana Special. However, it is still accessible from the selected car via links, so may be relevant.
  1. If vehicle is equipped with Content Theft Deterrent (CTD), go to next step. If vehicle is not equipped with CTD, go to step  3.
  2. If horns diagnostic system check was performed, go to next step. If horns diagnostic system check was not performed, perform HORNS DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
  3. Depress horn switch. If horns sound, check for intermittent problem. If horns do not sound, go to next step.
  4. Remove horn relay. Using a test light connected to ground, probe horn relay coil power feed circuit (Orange wire). See WIRING DIAGRAMS . If test light illuminates, go to next step. If test light does not illuminate, go to step  12.
  5. Connect a test light between battery positive voltage circuit of horn relay coil and horn relay control circuit (Black wire). Depress and hold horn switch. If test light illuminates, go to next step. If test light does not illuminate, go to step  13.
  6. Using test lamp connected to ground, probe battery voltage circuit of horn relay switch. If test lamp illuminates, go to next step. If test lamp does not illuminate, go to step  14.
  7. Momentarily connect a 15-amp fused jumper between battery voltage circuit of horn relay switch and horn control circuit. If horns sound, go to step  10. If horns do not sound, go to next step.
  8. Install horn relay. Disconnect either horn harness connector. Using a test light connected to ground, probe horn control circuit (Dark Green wire). Depress and hold horn switch. If test light illuminates, go to next step. If test light does not illuminate, go to step  15.
  9. Connect a test light between horn control circuit (Dark Green wire) and horn ground circuit (Black wire). Depress and hold horn switch. If test light illuminates, go to step  11. If test light does not illuminate, go to step  16.
  10. Inspect for poor connections at horn relay. If problem was found, repair as necessary. After repair, go to step  18. If problem was not found, go to step  17.
  11. Repair high resistance in horn control circuit (Dark Green wire) or horn ground circuit (Black wire). A resistance as low as.5 ohms could cause operating problems with horns. After repair, go to step  18.
  12. Repair open or high resistance in battery voltage circuit of horn relay coil. After repair, go to step  18.
  13. Disable SIR system. See appropriate AIR BAG RESTRAINT SYSTEMS article. Repair open or short to voltage in horn relay control circuit (Black wire). Horn relay control circuit includes horn slip ring and horn switch. After repair, go to step  18.
  14. Repair open or high resistance in battery voltage circuit of horn relay switch. After repair, go to step  18.
  15. Repair open or high resistance in horn control circuit (Dark Green wire). After repair, go to step  18.
  16. Repair open or high resistance in horn ground circuit (Black wire). After repair, go to step  18.
  17. Replace horn relay. After repair, go to next step.
  18. Operate horn to verify repair. If horns do not operate correctly, repeat test beginning at step  3.
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