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Section 336 (Horn System): Inspection

WARNING: This page is about a different car, the 2004 Toyota Sequoia. However, it is still accessible from the selected car via links, so may be relevant.
  1. INSPECT HORN SWITCH 
    1. Disconnect the negative (-) terminal from the battery.
    2. Remove the left and right covers from the steering wheel.
    3. Using a Torx socket wrench, loosen the 2 bolts.
    4. Pull up the horn pad and place it on the steering column, as shown.
      NOTE: Do not disconnect the connector from the horn pad.
    5. Disconnect the connector from the slip ring.
      Fig 1: Identifying Slip Ring Connector
      G02928202Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    6. Check that no continuity exists between terminal 6 of the connector and body ground. See Fig 2.
      Fig 2: Checking Continuity Between Connector Terminals And Ground
      G02928203Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    7. Check that continuity exists between terminal 6 of the connector and body ground when the horn contact plate is pressed against the steering spoke assembly.

      If continuity is not as specified, repair or replace the steering wheel or wire harness as necessary.

    8. Install the horn pad in place and using a Torx socket wrench, torque the 2 bolts.
      1. Torque: 7.1 N.m (62 in. lbs) 
    9. Install the left and right covers.
    10. Connect the negative (-) terminal to the battery.
  2. INSPECT HORN OPERATION 

    Connect the positive (+) lead from the battery to the terminal and negative (-) lead to the horn body and check that the horn blows.

    If operation is not as specified, replace the horn.

    3. Fig 3: Inspecting Horn Operation
    G02928204Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. INSPECT HORN SWITCH CIRCUIT (See  THEFT DETERRENT HORN CIRCUIT  ) 
  4. INSPECT HORN RELAY CONTINUITY 
    HORN RELAY CONTINUITY CHECK

    Condition Tester Connection Specified Condition
    Always 1 - 2 Continuity
    Always 3 - 5 No Continuity
    Apply B+ Between Terminals 1 And 2. 3 - 5 Continuity

    If continuity is not as specified, replace the relay.

  5. INSPECT HORN RELAY CIRCUIT See  ENGINE COMPARTMENT JUNCTION & RELAY BLOCKS  . 
    Fig 4: Identifying Horn Relay Terminal
    G02928205Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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