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.
On vehicles equipped with the high voltage system, disconnecting the 12-volt battery negative cable alone will not power down the 12-volt system. You must perform the 12-volt Power Down procedure before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.
A continuously sounding horn is immediately resolved by removing the horn relay from the Power Distribution Center (PDC).
| HORN SYSTEM DIAGNOSIS | ||
|---|---|---|
| CONDITION | POSSIBLE CAUSES | CORRECTION |
| HORN SOUNDS CONTINUOUSLY | 1. Damaged or ineffective horn feed circuit. | 1. Test and repair shorted horn feed circuit if required. |
| 2. Damaged or ineffective horn switch return circuit. | 2. Test and repair shorted horn switch return circuit if required. | |
| 3. Damaged or ineffective clockspring. | 3. Test and replace the shorted clockspring if required. | |
| 4. Damaged or ineffective horn switch plate. | 4. Test and replace the shorted horn switch plate (Driver AirBag/DAB) if required. | |
| 5. Damaged or ineffective horn relay. | 5. Test the horn relay inputs and outputs of the PDC. Replace the horn relay if required. | |
| HORN SOUNDS INTERMITTENTLY AS THE STEERING WHEEL IS ROTATED | 1. Damaged or ineffective horn switch return circuit. | 1. Test and repair intermittent shorted horn switch return circuit if required. |
| 2. Damaged or ineffective horn switch plate. | 2. Test and replace the intermittent open or shorted horn switch plate (DAB) if required. | |
| HORN DOES NOT SOUND | 1. Damaged or ineffective horn ground circuit. | 1. Test and repair open horn ground circuit if required. |
| 2. Damaged or ineffective horn feed circuit. | 2. Test and repair open horn feed circuit if required. | |
| 3. Damaged or ineffective horn. | 3. Test and replace open horn if required. | |
| 4. Damaged or ineffective horn switch feed circuit. | 4. Test and repair open horn switch feed circuit if required. | |
| 5. Damaged or ineffective horn switch return circuit. | 5. Test and repair open horn switch return circuit if required. | |
| 6. Damaged or ineffective clockspring. | 6. Test and replace the open clockspring if required. | |
| 7. Damaged or ineffective horn switch plate. | 7. Test and replace the open horn switch plate (DAB) if required. | |
| 8. Damaged or ineffective horn relay. | 8. Test the horn relay inputs and outputs of the PDC. Replace the horn relay if required. | |