HORN SYSTEM Vehicle Horn does not Sound

DESCRIPTION

When the horn button assembly is pressed, a signal is sent from the horn button assembly through the steering pad switch assembly to the spiral cable sub-assembly. The spiral cable sub-assembly and front light ECU (front controller) communicate via the CAN line. The front light ECU (front controller) receives the signal and sends it to the vehicle horns, causing the horns to sound.

WIRING DIAGRAM

A01GYUME03

INSPECTION PROCEDURE

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (HORN SWITCH)


    1. Using the intelligent tester, read the Data List Click here.

      Steering Pad Switch
      Tester Display

      Measurement Item /

      Display (Range)

      		 Normal Condition Diagnostic Note
      Horn switch

      Horn button status

      / ON or OFF

      ON: Horn button is pressed

      OFF: Horn button is not pressed

      		 -
      OK
      ON (horn button is pressed) appears on screen.

    NG

    CHECK HORN BUTTON ASSEMBLY Click here

    OK

  2. INSPECT HORN ASSEMBLY

    A01GY0XE02

    1. Remove the low pitched horn Click here or high pitched horn Click here.

    2. Apply battery voltage and check the operation of the horn.

      OK
      Measurement Condition Specified Condition

      Battery positive (+) → Terminal 1

      Battery negative (-) → Horn bracket

      		 Horn sounds
      Result
      Result Proceed to
      Both horns sound normally A
      High pitched horn does not sound B
      Low pitched horn does not sound C

    B

    REPLACE HIGH PITCHED HORN ASSEMBLY Click here

    C

    REPLACE LOW PITCHED HORN ASSEMBLY Click here

    A

  3. CHECK HARNESS AND CONNECTOR (FRONT LIGHT ECU - HORN)

    A01GYH8E10

    1. Disconnect the B14 ECU connector.

    2. Disconnect the B6*1 or B10*2 horn connector.


      • *1: for High Pitched Horn

      • *2: for Low Pitched Horn

    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      for High Pitched Horn
      Tester Connection Condition Specified Condition
      B14-2 (HORH) - B6-1 Always Below 1 Ω
      B14-2 (HORH) or B6-1 - Body ground Always 10 kΩ or higher
      for Low Pitched Horn
      Tester Connection Condition Specified Condition
      B14-1 (HORL) - B10-1 Always Below 1 Ω
      B14-1 (HORL) or B10-1 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK STEERING PAD SWITCH ASSEMBLY


    1. Temporarily replace the steering pad switch assembly with a new or normally functioning one Click here.

    2. Check that the vehicle horns operate normally.

      OK
      Vehicle horns operate normally.

    NG

    REPLACE FRONT LIGHT ECU (FRONT CONTROLLER)

    OK

    END (STEERING PAD SWITCH ASSEMBLY WAS DEFECTIVE)

  5. CHECK HORN BUTTON ASSEMBLY


    1. Temporarily replace the horn button assembly with a new or normally functioning one Click here.

    2. Check that the vehicle horns operate normally.

      OK
      Vehicle horns operate normally.

    NG

    CHECK STEERING PAD SWITCH ASSEMBLY Click here

    OK

    END (HORN BUTTON ASSEMBLY WAS DEFECTIVE)

  6. CHECK STEERING PAD SWITCH ASSEMBLY


    1. Temporarily replace the steering pad switch assembly with a new or normally functioning one Click here.

    2. Check that the vehicle horns operate normally.

      OK
      Vehicle horns operate normally.

    NG

    REPLACE FRONT LIGHT ECU (FRONT CONTROLLER)

    OK

    END (STEERING PAD SWITCH ASSEMBLY WAS DEFECTIVE)