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

DESCRIPTION

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WIRING DIAGRAM

A01WZGAE10
A01WZGAE11

CAUTION / NOTICE / HINT

Tech Tips


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

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

PROCEDURE


  1. INSPECT STEERING WHEEL ASSEMBLY (THERMISTOR,HEATER,THERMOSTAT)


    1. A01X9E1E06
      Text in Illustration
      *a

      Component without harness connected

      (Steering Wheel Assembly)

      Disconnect the B steering wheel heater control 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

    NG

    REPLACE STEERING WHEEL ASSEMBLY Click here

    OK

  2. INSPECT SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY


    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 E140*1 or E107*2 and z74 spiral with sensor cable sub-assembly connectors.


      • *1: w/ Door Ajar Warning Buzzer

      • *2: w/o Door Ajar Warning Buzzer

      A01X0H0E02
      Text in Illustration
      *A w/ Door Ajar Warning Buzzer *B w/o Door Ajar Warning Buzzer
      *a

      Component without harness connected

      (Spiral with Sensor Cable Sub-assembly)

      		 - -

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

      Standard Resistance
      w/ Door Ajar Warning Buzzer
      Tester Connection Condition Specified Condition
      z74-1 - E140-1 (BTM) Always Below 1 Ω
      z74-2 - E140-3 (ETM) Always Below 1 Ω
      z74-3 - E140-2 (EHT) Always Below 1 Ω
      z74-4 - E140-4 (BHT) Always Below 1 Ω
      w/o Door Ajar Warning Buzzer
      Tester Connection Condition Specified Condition
      z74-1 - E107-1 (BTM) Always Below 1 Ω
      z74-2 - E107-3 (ETM) Always Below 1 Ω
      z74-3 - E107-2 (EHT) Always Below 1 Ω
      z74-4 - E107-4 (BHT) Always Below 1 Ω

    NG

    REPLACE SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY Click here

    OK

  3. INSPECT REFRESHING SEAT SWITCH (STEERING HEATER SWITCH)


    1. Remove the steering heater switch Click here.

    2. Inspect the steering heater switch Click here.


    NG

    REPLACE REFRESHING SEAT SWITCH Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (STEERING HEATER SWITCH - SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY)


    1. Disconnect the V7 steering heater switch connector.

    2. Disconnect the E140*1 or E107*2 spiral with sensor cable sub-assembly connector.


      • *1: w/ Door Ajar Warning Buzzer

      • *2: w/o Door Ajar Warning Buzzer

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

      Standard Resistance
      w/ Door Ajar Warning Buzzer
      Tester Connection Condition Specified Condition
      V7-4 (+) - E140-1 (BTM) Always Below 1 Ω
      V7-8 (IN) - E140-3 (ETM) Always Below 1 Ω
      w/o Door Ajar Warning Buzzer
      Tester Connection Condition Specified Condition
      V7-4 (+) - E107-1 (BTM) Always Below 1 Ω
      V7-8 (IN) - E107-3 (ETM) Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (IG CIRCUIT)


    1. Disconnect the V7 steering heater switch connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      V7-1 (IG) - Body ground Ignition switch ON 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (IG CIRCUIT)


    1. Disconnect the E140*1 or E107*2 spiral with sensor cable subassembly connector.


      • *1: w/ Door Ajar Warning Buzzer

      • *2: w/o Door Ajar Warning Buzzer

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

      Standard Voltage
      w/ Door Ajar Warning Buzzer
      Tester Connection Switch Condition Specified Condition
      E140-4 (BHT) - Body ground Ignition switch ON 11 to 14 V
      w/o Door Ajar Warning Buzzer
      Tester Connection Switch Condition Specified Condition
      E107-4 (BHT) - Body ground Ignition switch ON 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Disconnect the E140*1 or E107*2 spiral with sensor cable sub-assembly connector.


      • *1: w/ Door Ajar Warning Buzzer

      • *2: w/o Door Ajar Warning Buzzer

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

      Standard Resistance
      w/ Door Ajar Warning Buzzer
      Tester Connection Condition Specified Condition
      E140-2 (EHT) - Body ground Always Below 1 Ω
      w/o Door Ajar Warning Buzzer
      Tester Connection Condition Specified Condition
      E107-2 (EHT) - Body ground Always Below 1 Ω

    OK

    REPLACE STEERING WHEEL ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR