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DTC B2753: Horn Relay Coil Circuit High (Century & Regal): Testing

  1. If horns diagnostic system check was performed, go to next step. If horns diagnostic system check was not performed, see HORNS DIAGNOSTIC SYSTEM CHECK (CENTURY & REGAL)  under SELF-DIAGNOSTIC SYSTEM.
  2. Connect scan tool to Data Link Connector (DLC). DLC is located below left side of instrument panel, to right of steering column. Turn ignition switch to RUN position. Using scan tool, command horn relay ON and OFF. If horn relay does not click with each command, go to next step. If horn relay clicks with each command, go to DIAGNOSTIC AIDS  .
  3. Turn ignition switch to OFF position. Remove horn relay from underhood fuse block, located on right side of engine compartment, mounted to strut tower. Turn ignition switch to RUN position. Connect test light between ground and horn relay coil power supply circuit cavity No. 85 (Black wire). See Figure . If test light illuminates, go to next step. If test light does not illuminate, go to step  10 .
  4. Connect test light between horn relay cavities No. 85 (coil power supply circuit) and No. 86 (relay control circuit). Using scan tool, command horn relay ON and OFF. If test light does not turn on and off with each command, go to next step. If test light turns on and off with each command, go to step  8 .
  5. If test light did not remain illuminated with horn relay ON and OFF command, go to next step. If test light remained illuminated with horn relay ON and OFF command, go to step  7 .
  6. Check for an open in horn relay control circuit (Black wire) between horn relay cavity No. 86, BCM Light Blue 24-pin harness connector C3 terminal A5 and horn switch harness connector. See Figure . Repair as necessary and retest system. If circuit is okay, go to step  9 .
  7. Check for short to ground in horn relay control circuit (Black wire) between horn relay cavity No. 86, BCM Light Blue 24-pin connector C3 terminal A5 and horn switch harness connector. See Figure and Figure . If circuit is okay, go to step  9 . If circuit is not okay, repair as necessary. After repair, go to step  13 .
  8. Check horn relay connector for poor connections. Repair as necessary and retest system. If connector is okay, replace horn relay and After repair, go to step  13 .
  9. Check BCM connector C3 for intermittent or poor terminal contact. If terminal contact is okay, go to step  12 . If terminal contact is not okay, repair as necessary. After repair, go to step  13 .
  10. Repair open in Black wire between horn relay cavity No. 86, BCM and horn switch harness connector. After repair, go to step  13 .
  11. Replace horn relay. After repair, go to step  13 .
  12. Replace BCM. Program as necessary. See BODY CONTROL MODULES - CENTURY & REGAL article. After repair, go to next step.
  13. Using scan tool, clear DTCs. Operate system to verify fault no longer exists. If fault still exists, go to step  2 .
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