2023-2025 Jeep/RAM Horn Sound Weak or Inoperative TSB S2423000027

Symptoms

Owners of 2023-2025 Jeep and RAM vehicles may experience issues with their vehicle's horn, specifically reporting that the "Horn Sound Is Weak, Off Tone, Inoperative, Or Intermittent". This means the horn might not sound as loud as it should, have an unusual tone, not work at all, or only work sometimes. These symptoms directly impact vehicle safety by reducing the effectiveness of the horn as a warning device.

Diagnosis and Initial Checks

When a Jeep RAM horn sound issue is reported, technicians are advised to begin by recording any Diagnostic Trouble Codes (DTCs) and performing initial diagnostics. A critical first step involves verifying the integrity of the 20A fuse located in the Power Distribution Center (PDC). The correct fuse number varies by model:

• For DT models: Fuse F40 or F57
• For DJ, D2, DD, DP models: Fuse F42
• For JL, JT models: Fuse F91
• For WS models: Fuse F66 The fuse must be fully inserted and making proper connection. Technicians should also ensure both the low and high note horns sound correctly. If the horn sound is weak or abnormal, further investigation is required.

Repair Procedure Summary

Technical Service Bulletin S2423000027 outlines a detailed diagnostic and repair process for technicians.

1. Horn Bench Testing: After turning off the ignition, technicians disconnect the horns and test them using a terminal test kit. The horns should operate between 9.3V and 16V, ideally at 13V, with a maximum current draw of 6 amps for a single horn or 12 amps for dual horns. It's important to note that low battery voltage can cause horn tones to weaken. If a horn is found to be inoperative during this test, it should be replaced.

2. Harness and Connector Inspection: If the horns pass the bench test, the next step involves disconnecting all harness connectors from the Power Distribution Center (PDC), Body Control Module (BCM), or Steering Column Control Module (SCCM) for the circuit under test. Technicians must thoroughly inspect these connectors, components, and terminals for issues such as improper installation, damaged connector locks, corrosion, signs of water intrusion, bent terminals, overheating (indicated by discolored terminals), or terminals pushed into the connector cavity. A terminal drag test is also performed to check for proper tension.

3. DTC Clearance and Re-evaluation: After reconnecting all harness connectors, any existing DTCs are cleared using a scan tool. The vehicle is then operated under the conditions that initially triggered the horn issue, and current DTCs are re-checked. If BCM or SCCM-related DTCs are still present, the affected assembly (PDC, BCM, or SCCM) should be replaced, followed by a Body Test.

4. Clock Spring and Horn Switch Check: If the horn sounds intermittently while turning or driving, the Clock Spring in the SCCM should be checked for a possible short circuit, assuming the wiring is in good condition. The horn switch itself, which is integrated into the Driver Airbag (DAB) and is non-repairable, must also be verified for proper operation. If the horn switch is faulty or damaged, the entire DAB assembly needs replacement. Technicians should refer to service instructions "08 - Electrical / 8H - Horn / SWITCH, Horn / Diagnosis and Testing" for detailed guidance.

5. Circuit Voltage and Continuity Testing: As a final step, with the ignition on, technicians use a Digital Volt-Ohm Meter to measure voltage from the PDC relay output to the horn, while an assistant presses the horn button. Ground at the BCM low current relay coil harness connectors is also checked.

   • If voltage is present, the circuit is checked and repaired for a voltage short.
   • If no voltage is present, the PDC harness is inspected for open circuits or connection issues.
   • If there is continuity to ground, the circuit is checked and repaired for a ground short.
   • If there is no continuity to ground, the BCM harness connections are checked for issues.

Required Tools or Parts

For proper diagnosis and repair, technicians are advised to use Test Lead Kit 2064100081 for probing terminals. This kit helps prevent damage to pins during testing.

Owner Action

If your 2023-2025 Jeep or RAM vehicle exhibits a Jeep RAM horn sound that is weak, off-tone, inoperative, or intermittent, it is recommended to schedule an appointment with an authorized dealership. Technicians will follow the procedures outlined in TSB S2423000027 to accurately diagnose and resolve the problem. This communication does not authorize warranty repairs, so discuss potential costs with your service advisor.

NHTSA Source Citation

NHTSA ID: 11015602