Horn

This procedure covers the diagnosis, removal, and replacement of the horn assembly on a 2007 Ram 3500 with 5.9L Cummins diesel engine.

Warnings

Tools required

Parts

• Horn assembly × 1 — Mopar 68003860AA or equivalent

Preparation

1. Park vehicle on level ground and engage parking brake
2. Disconnect negative battery terminal and wait 2 minutes before proceeding
3. Locate the horn assembly mounted on the driver side frame rail behind the front bumper

Procedure

1. 1

   Diagnose horn circuit
   Before removing the horn, verify the issue is with the horn itself and not the circuit. Locate the horn fuse in the Power Distribution Center (PDC/Totally Integrated Power Module) under the hood and check continuity (refer to the PDC lid diagram or owner's manual for the exact horn fuse cavity and rating). If fuse is good, have an assistant press the horn button while you listen for relay click in the PDC. If relay clicks but horn doesn't sound, proceed with horn replacement.
2. 2

   Access horn assembly
   The horn is mounted near the front of the vehicle behind the bumper/grille area, typically attached to the radiator core support or frame bracket. Verify exact location and whether the vehicle has single or dual horns before proceeding. For better access, turn the steering wheel fully to the right. You may be able to reach the horn from above through the engine bay, or from below by reaching up behind the bumper. On 4WD models, access is more restricted due to front differential placement.
3. 3

   Test horn electrical connection
   Before removing the horn, reconnect the battery temporarily. Use a test light or multimeter to verify power at the horn connector while an assistant presses the horn button. If no power is present, trace wiring back toward the PDC for breaks or corrosion. If power is present and horn doesn't sound, the horn is faulty.
4. 4

   Disconnect battery again
   Disconnect the negative battery terminal again before proceeding with removal to prevent accidental short circuits during the repair.
5. 5

   Disconnect horn electrical connector
   Locate the wire connector on the horn assembly (single-wire if ground is through the bracket, or two-wire if grounded through the harness). Press the connector release tab and pull the connector straight off the horn terminal. Inspect the connector terminal for corrosion or damage.
6. 6

   Remove horn mounting bolt
   Remove the bolt(s) securing the horn bracket to the mount (commonly a 10mm or 13mm head). Verify the fastener size and count on your vehicle. Support the horn while removing the bolt to prevent it from falling. Note the orientation of the horn and bracket for reinstallation. Support the horn while removing the bolt to prevent it from falling. Note the orientation of the horn and bracket for reinstallation.
7. 7

   Remove horn assembly
   Carefully maneuver the horn assembly out from its mounting location. On 4WD models, you may need to rotate the horn to clear the differential and other components. Inspect the mounting bracket for damage or excessive corrosion.
8. 8

   Prepare mounting location
   Clean the frame rail mounting surface with a wire brush to ensure good electrical ground. Remove any rust, dirt, or corrosion. Clean the mounting surface of rust and dirt for a secure fit. Note: some horns ground through the mounting bracket while others ground through the harness (two-wire connector). If this horn uses a bracket ground, ensure clean metal-to-metal contact.
9. 9

   Install new horn assembly
   Position the new horn assembly in the mounting bracket with the same orientation as the original. Align the mounting hole with the frame rail. Thread the mounting bolt by hand initially to ensure proper alignment.
10. 10

    Tighten mounting bolt
    Using a 10mm socket, tighten the horn mounting bolt securely. Ensure the horn bracket makes solid contact with the frame rail for proper grounding. Do not overtighten as the bracket can deform.
11. 11

    Connect electrical connector
    Push the electrical connector firmly onto the horn terminal until it clicks into place. Ensure the connection is secure and the locking tab is fully engaged. Verify the connector cannot be pulled off without pressing the release tab.
12. 12

    Reconnect battery
    Reconnect the negative battery terminal and tighten the terminal clamp securely.

Reassembly

1. No additional reassembly required beyond reconnecting the battery

Verification

• Turn ignition to the ON position without starting the engine
• Press the horn button on the steering wheel and verify the horn sounds with proper volume and tone
• Test the horn multiple times with short and long presses to ensure consistent operation
• If horn still does not work, verify ground connection at mounting bolt and check for voltage at horn terminal with button pressed

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