Test A: Horns Always On

2001 Chevrolet Cavalier LS, 2.4 TSECTION Test A: Horns Always On
  1. If horns diagnostic system check has been performed, go to next step. If horns diagnostic system check has not been performed, perform HORNS DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
  2. Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). DLC is located under left side of instrument panel. Turn ignition switch to RUN position. Using scan tool, command Body Control Module (BCM) horn output On and Off. If horns sound continuously, go to next step. If horns do not sound continuously, horn concern may be intermittent. See PRELIMINARY INSPECTION  under TROUBLE SHOOTING.
  3. Turn ignition switch to OFF position. Remove horn relay from underhood junction block. Underhood junction block is located at left side of engine compartment (Alero & Grand Am) and right front corner of engine compartment, near A/C accumulator (Cavalier & Sunfire). If horns do not sound continuously, go to next step. If horns sound continuously, go to step  8 .
  4. Connect a test light between battery voltage terminal of horn relay coil voltage supply and horn relay control circuits. See WIRING DIAGRAMS  . If test light illuminates, go to next step. If test light does not illuminate, go to step  6 .
  5. Disable air bag system. See AIR BAG RESTRAINT SYSTEMS article. For 2002, see AIR BAG RESTRAINT SYSTEMS article. Check for short to ground in horn relay control circuit. Horn relay control circuit includes horn slip ring and horn switch. See WIRING DIAGRAMS  . If problem is found, repair as necessary and go to step  11 . If no problem is found, go to step  7 .
  6. Check for poor, loose or corroded terminals in horn relay socket connector. If problem is found, repair as necessary an go to step  11 . If no problem is found, go to step  9 .
  7. Check for poor, loose or corroded terminals at BCM harness connector C1. If problem is found, repair as necessary an go to step  11 . If no problem is found, go to step  10 .
  8. Repair short to voltage in horn control circuit. See WIRING DIAGRAMS  . After repairs are made, go to step  11 .
  9. Replace horn relay. After repairs are made, go to step  11 .
  10. Replace BCM. See BODY CONTROL MODULES article. For 2002, see BODY CONTROL MODULES article. After repairs are made, go to next step.
  11. Operate horns. If horns operate normally, testing is complete. If horns do not operate normally, go to step  2 .
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.