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Grand Prix

  1. If vehicle is equipped with content theft deterrent system, go to next step. If vehicle is not equipped with content theft deterrent system, go to step  3 .
  2. If horns diagnostic system check has been performed, go to step  4 . If horns diagnostic system check has not been performed, go to HORNS DIAGNOSTIC SYSTEM CHECK (GRAND PRIX)  under SELF-DIAGNOSTIC SYSTEM.
  3. If horn description and operation has been reviewed and preliminary inspection has been performed, go to next step. If horn description and operation has not been reviewed and/or preliminary inspection has not been performed, go to DESCRIPTION & OPERATION  and PRELIMINARY INSPECTION  under TROUBLESHOOTING.
  4. Press horn switch. If horns do not operate, go to next step. If horns operate, check for intermittent or poor terminal contact. Repair as necessary.
  5. Remove horn relay from underhood fuse block, located in right side of engine compartment, mounted to strut tower. Connect test light between ground and horn relay coil battery positive voltage circuit terminal. If test light illuminates, got o next step. If test light does not illuminate, go to step  15 .
  6. Connect test light between horn relay coil battery positive voltage circuit socket and horn relay control circuit socket. Press and hold horn switch. If test light illuminates, go to next step. If test light does not operate, go to step  16 .
  7. Connect test light between ground and horn relay switch battery positive voltage circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step  17 .
  8. Momentarily connect a fused (15-amp) jumper wire between horn relay switch battery positive voltage circuit socket and horn control circuit socket. If horns do not operate, go to next step. If horns operate, go to step  11 .
  9. Install horn relay. Disconnect horn harness connector. Connect test light between ground and horn harness connector Dark Green wire terminal. Press and hold horn switch. If test light illuminates, go to next step. If test light does not illuminate, go to step  18 .
  10. Connect test light between horn harness connector Dark Green wire and Black wire terminals. Press and hold horn switch. If test light illuminates, go to step  12 . If test light does not illuminate, go to step  19 .
  11. Check horn relay connector for intermittent or poor terminal contact. If terminal contact is okay, go to step  20 . If terminal contact is not okay, repair as necessary. After repair, go to step  22 .
  12. Check horn connector for intermittent or poor terminal contact. If terminal contact is okay, go to next step. If terminal contact is not okay, repair as necessary. After repair, go to step  22 .
  13. Connect a fused (15-amp) jumper wire between battery positive terminal and horn Dark Green wire terminal (component side). Momentarily connect a second fused jumper wire between battery ground terminal and horn Black wire terminal (component side). If horn sounds, go to next step. If horn does not sound, go to step  21 .
    14. NOTE: A resistance as low as 0.5 ohms can cause operating problems with horn system.
  14. Repair high resistance in horn control circuit (Dark Green wire) or horn ground circuit (Black wire). After repair, go to step  22 .
  15. Repair open or high resistance in horn relay coil battery positive voltage circuit. After repair, go to step  22 .
    16. CAUTION: Horn switch is part of inflatable restraint steering wheel module. Disable air bag system. See SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM in appropriate AIR BAG RESTRAINT SYSTEMS article.
  16. Repair open or short to voltage in horn relay control circuit (Black wire) between horn switch, underhood fuse block, vehicle interface unit and/or BCM. After repair, go to step  22 .
  17. Repair open or high resistance in horn relay switch battery positive voltage circuit. After repair, go to step  22 .
  18. Repair open or high resistance in Dark Green wire between horn relay and horns. After repair, go to step  22 .
  19. Repair open or high resistance in horn ground circuit (Black wire) between horns and ground. Ground point (G101) is located at left side of front end upper tie bar, near headlight. See Figure . After repair, go to step  22 .
  20. Replace horn relay. After repair, go to step  22 .
  21. Replace horn assembly. After repair, go to next step.
  22. Operate horn system to verify fault no longer exists. If fault still exists, go to step  1 .
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