Diagnosis And Testing - Horn System
To avoid serious or fatal injury on vehicles equipped with airbags, disable the Supplemental Restraint System (SRS) before attempting any steering wheel, steering column, airbags, airbag curtains, knee blocker, seat belt tensioner, impact sensor or instrument panel component diagnosis or service. Disconnect the Intelligent Battery Sensor (IBS)/negative battery cable assembly from the negative battery post, then wait two minutes for the system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the SRS. Failure to take the proper precautions could result in accidental airbag deployment.
A continuously sounding horn is immediately silenced by removing the horn fuse from the Power Distribution Center (PDC).
| HORN SYSTEM DIAGNOSIS | ||
|---|---|---|
| CONDITION | POSSIBLE CAUSES | CORRECTION |
| HORN SOUNDS CONTINUOUSLY | 1. Damaged or ineffective fused horn control output circuit. | 1. Test and repair shorted fused horn control output circuit if required. |
| 2. Damaged or ineffective horn relay. | 2. Test the horn relay inputs and outputs of the Power Distribution Center (PDC). Replace the PDC if required. | |
| 3. Damaged or ineffective horn sense circuit. | 3. Test and repair shorted horn sense circuit if required. | |
| 4. Damaged or ineffective horn switch. | 4. Test and replace the shorted horn switch, mounting plate and Driver AirBag (DAB) as a unit if required. | |
| 5. Damaged or ineffective horn relay control circuit. | 5. Test and repair shorted horn relay control circuit if required. | |
| 6. Damaged or ineffective Steering Column Control Module (SCCM). | 6. Test and replace the shorted SCCM if required. | |
| 7. Damaged or ineffective Body Control Module (BCM). | 7. Test and repair shorted BCM if required. | |
| HORN SOUNDS INTERMITTENTLY AS THE STEERING WHEEL IS ROTATED | 1. Damaged or ineffective SCCM. | 1. Test and repair intermittent shorted SCCM if required. |
| 2. Damaged or ineffective horn switch. | 2. Test and replace the intermittent open or shorted horn switch, mounting plate and DAB as a unit if required. | |
| HORN DOES NOT SOUND | 1. Damaged or ineffective horn fuse. | 1. Test and repair open horn fuse if required. |
| 2. Damaged or ineffective horn ground circuit. | 2. Test and repair open horn ground circuit if required. | |
| 3. Damaged or ineffective fused horn control output circuit. | 3. Test and repair open fused horn control output circuit if required. | |
| 4. Damaged or ineffective horn. | 4. Test and replace open horn if required. | |
| 5. Damaged or ineffective horn relay control circuit. | 5. Test and replace the open horn relay control circuit if required. | |
| 6. Damaged or ineffective horn sense circuits. | 6. Test and repair open horn sense circuit if required. | |
| 7. Damaged or ineffective horn switch. | 7. Test and replace the open horn switch, mounting plate and DAB as a unit if required. | |
| 8. Damaged or ineffective horn relay. | 8. Test the horn relay inputs and outputs of the PDC. Replace the PDC if required. | |
| 9. Damaged or ineffective SCCM. | 9. Test and replace the open SCCM if required. | |
| 10. Damaged or ineffective BCM. | 10. Test and repair open BCM if required. | |