HEATED STEERING WHEEL SYSTEM Steering Wheel does not Heat Up When Heated Steering Wheel Switch is Pressed

DESCRIPTION

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WIRING DIAGRAM

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CAUTION / NOTICE / HINT

Tech Tips


  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

  • The steering wheel heater unit is built into the steering wheel assembly which cannot be disassembled. Therefore, when the steering wheel heater unit has a malfunction, replace the steering wheel assembly.

PROCEDURE


  1. INSPECT STEERING WHEEL HEATER UNIT (THERMISTOR/HEATER/THERMOSTAT)


    1. w/o Steering Wheel Vibration:


      1. B005AODC08
        *a

        Front view of wire harness connector

        (to Steering Wheel Heater Control Assembly)

        Disconnect the B steering wheel heater control assembly connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        B-1 (TH1) - B-2 (TH2) 10 to 30°C (50 to 86°F) 8.132 to 18.43 kΩ
        B-4 (SH1) - B-3 (SH2) 20°C (68°F) 1.89 to 2.25 Ω

    2. w/ Steering Wheel Vibration:


      1. B005AG4C09
        *a

        Front view of wire harness connector

        (to Steering Vibration and Heater ECU)

        Disconnect the B steering vibration and heater ECU connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        B-3 (TH1) - B-2 (TH2) 10 to 30°C (50 to 86°F) 8.132 to 18.43 kΩ
        B-5 (SH1) - B-1 (SH2) 20°C (68°F) 1.91 to 2.25 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE STEERING WHEEL ASSEMBLY Click here

    OK

  2. INSPECT SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY


    1. w/o Steering Wheel Vibration:


      1. Check the connectors and cables of the spiral with sensor cable sub-assembly.

        OK
        There are no defects such as scratches, cracks, dents or damage on the connectors or cables.

      2. Disconnect the I157 and z14 spiral with sensor cable sub-assembly connectors.

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

        B0058IMC21
        *a

        Component without harness connected

        (Spiral with Sensor Cable Sub-assembly)

        		 - -
        Standard Resistance
        Tester Connection Condition Specified Condition
        z14-1 - I157-1 (BTM) Always 3 Ω or less
        z14-2 - I157-3 (ETM) Always 3 Ω or less
        z14-3 - I157-2 (EHT) Always Below 0.1 Ω
        z14-4 - I157-4 (BHT) Always Below 0.1 Ω

    2. w/ Steering Wheel Vibration:


      1. Check the connectors and cables of the spiral cable with sensor sub-assembly.

        OK
        There are no defects such as scratches, cracks, dents or damage on the connectors or cables.

      2. Disconnect the I157 and z13 spiral cable with sensor sub-assembly connectors.

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

        B0059CRC05
        *a

        Component without harness connected

        (Spiral Cable with Sensor Sub-assembly)

        		 - -
        Standard Resistance
        Tester Connection Condition Specified Condition
        z13-2 - I157-1 (BTM) Always 3 Ω or less
        z13-3 - I157-3 (ETM) Always 3 Ω or less
        z13-1 - I157-2 (EHT) Always 0.02 to 0.28 Ω
        z13-4 - I157-4 (BHT) Always 0.02 to 0.28 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY Click here

    OK

  3. INSPECT NO. 2 COMBINATION SWITCH ASSEMBLY (STEERING HEATER SWITCH)


    1. Remove the No. 2 combination switch assembly.

      Click here

    2. Inspect the No. 2 combination switch assembly (steering heater switch).

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE NO. 2 COMBINATION SWITCH ASSEMBLY Click here

    OK

  4. CHECK STEERING HEATER RELAY


    1. B00599UC03
      *1 STRG HTR Relay

      Remove the STRG HTR relay from the No. 2 engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 - 5 Voltage is not applied between terminals 1 and 2 10 kΩ or higher
      3 - 5 Voltage is applied between terminals 1 and 2 Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE STEERING HEATER RELAY

    OK

  5. CHECK HARNESS AND CONNECTOR (NO. 2 COMBINATION SWITCH ASSEMBLY - SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY)


    1. Disconnect the I37 No. 2 combination switch assembly connector.

    2. Disconnect the I157 spiral with sensor cable sub-assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I37-16 (ECU) - I157-3 (ETM) Always Below 1 Ω
      I37-9 (IND) - I157-1 (BTM) Always Below 1 Ω
      I37-16 (ECU) or I157-3 (ETM) - Body ground Always 10 kΩ or higher
      I37-9 (IND) or I157-1 (BTM) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (STRG HTR RELAY - SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY)


    1. Remove the STRG HTR relay from the No. 2 engine room relay block.

    2. Disconnect the I157 spiral with sensor cable sub-assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      5 - I157-4 (BHT) Always Below 1 Ω
      5 or I157-4 (BHT) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. CHECK HARNESS AND CONNECTOR (NO. 2 COMBINATION SWITCH ASSEMBLY POWER SOURCE)


    1. B005B8HC05
      *a

      Front view of wire harness connector

      (to No. 2 Combination Switch Assembly)

      Disconnect the I37 No. 2 combination switch assembly connector.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      I37-4 (IG1) - Body ground Engine switch on (IG) 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. CHECK HARNESS AND CONNECTOR (STRG HTR RELAY POWER SOURCE)


    1. Remove the STRG HTR relay from the No. 2 engine room relay block.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      3 - Body ground Always 11 to 14 V
      1 - Body ground Engine switch on (IG) 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2 - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. CHECK HARNESS AND CONNECTOR (SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY BODY GROUND)


    1. Disconnect the I157 spiral with sensor cable sub-assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I157-2 (EHT) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE STEERING WHEEL HEATER CONTROL ASSEMBLY w/o Steering Wheel Vibration: REPLACE STEERING WHEEL HEATER CONTROL ASSEMBLY Click here
    REPLACE STEERING WHEEL HEATER CONTROL ASSEMBLY w/ Steering Wheel Vibration: REPLACE STEERING WHEEL HEATER CONTROL ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR