2021-2022 Nissan Horn Inoperative TSB NTB22-051

Symptoms

Owners of affected Nissan vehicles may experience an "inoperative horn". This means the horn does not sound when activated, which can be a significant safety concern.

Diagnosis and Trigger Conditions

This TSB applies if you confirm that the horn on your 2021-2022 Nissan vehicle is inoperative. The underlying cause is typically a pinched horn ground wire within the horn pad assembly. A technician will need to inspect the horn pad to confirm the presence of a pinched ground wire.

Repair Procedure Summary

The repair for a Nissan horn inoperative condition involves several steps to safely access and replace the horn components:

1. Prepare the Vehicle: Technicians will first record radio settings and then open the hood to disconnect the negative battery terminal. The ignition must be OFF, and protective tape is applied over the disconnected terminal. A minimum of 3 minutes must pass after battery disconnection to allow the airbag diagnosis unit to discharge.
2. Access Airbag Module: The steering wheel is turned to expose access holes on the back and bottom. A special Air Bag Release Tool (J-52551) is used to disengage the springs holding the driver airbag module in place.
3. Remove Airbag Module: The driver airbag module is carefully pulled out after the springs are released.
4. Inspect Ground Wire: The horn ground wire is then inspected for any signs of pinching. This is a critical step to identify the root cause of the Nissan horn inoperative issue.
5. Replace Horns: If a pinched ground wire is found, both the high and low horns are replaced. If no pinched wire is present, the repair proceeds to reinstallation.
6. Reinstall Airbag Module: The driver airbag module is reinstalled in reverse order. During this step, the module is rotated 360 degrees to remove excess slack from the ground wire and prevent future pinching.
7. Reconnect Battery: The negative battery terminal is reconnected.
8. Final Checks: Additional service procedures related to 12V battery negative terminal removal are performed, and the horn is tested to ensure correct operation.

Required Tools or Parts

To perform this repair, Nissan technicians will use specific tools and parts:

• Air Bag Release Tool: Special tool J-52551.
• Horn Assembly – Electric High: Part number 25610-***** (the full part number will be determined using the VIN in the Electronic Parts Catalog).
• Horn Assembly – Electric Low: Part number 25620-***** (the full part number will be determined using the VIN in the Electronic Parts Catalog).

Important Warnings for Owners

Nissan has issued several important advisories regarding this technical service bulletin:

• "Bulletins are intended for use by qualified technicians, not 'do-it-yourselfers'. Qualified technicians are properly trained individuals who have the equipment, tools, safety instruction, and know-how to do a job properly and safely."
• "If you believe that a described condition may apply to a particular vehicle, DO NOT assume that it does. See your Nissan dealer to determine if this applies to your vehicle."
• "To prevent damage to the ACC power supply, do not operate the vehicle, such as locking/unlocking or opening/closing the doors within the 3 minute waiting period." after disconnecting the battery.
• "To prevent the risk of personal injury or damage to the vehicle, verify the ignition switch is OFF and a minimum of 3 minutes has elapsed since the negative battery terminal was disconnected, before proceeding to step 3."
• "The pinched ground wire does not require a wire repair." The solution is to replace the horns and ensure proper wire routing during reinstallation.

Source: NHTSA ID 10218701