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

DESCRIPTION

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WIRING DIAGRAM

A0005QEE20

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. A00055TE07
      Text in Illustration
      *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

    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 H76 and z4 spiral with sensor cable sub-assembly connectors.

      A00082ZE02

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      z4-1 (BTM) - H76-1 (BTM) Always 3 Ω or less
      z4-2 (ETM) - H76-3 (ETM) Always 3 Ω or less
      z4-3 (EHT) - H76-2 (EHT) Always Below 0.1 Ω
      z4-4 (BHT) - H76-4 (BHT) Always Below 0.1 Ω
      Text in Illustration
      *a

      Component without harness connected

      (Spiral with Sensor Cable Sub-assembly)

      		 - -

    NG

    REPLACE SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY Click here

    OK

  3. CHECK STEERING HEATER SWITCH (COMBINATION SWITCH ASSEMBLY)


    1. A00092HE05
      Text in Illustration
      *a

      Component without harness connected

      (Steering Heater Switch (Combination Switch Assembly))

      Disconnect the H37 steering heater switch (combination switch assembly) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      9 (IG) - 3 (IN) Steering heater switch (combination switch assembly) is pushed Below 1 Ω
      9 (IG) - 3 (IN) Steering heater switch (combination switch assembly) is not pushed 10 kΩ or higher

    NG

    REPLACE STEERING HEATER SWITCH (COMBINATION SWITCH ASSEMBLY) Click here

    OK

  4. CHECK STRG HTR RELAY (STEERING HEATER RELAY)


    1. A0005Y3E06
      Text in Illustration
      *1 STRG HTR Relay (Steering Heater Relay)

      Remove the STRG HTR relay (steering heater relay).

    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

    NG

    REPLACE STRG HTR RELAY (STEERING HEATER RELAY)

    OK

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


    1. Disconnect the H37 steering heater switch (combination switch assembly) connector.

    2. Disconnect the H76 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
      H37-4 (+) - H76-1 (BTM) Always Below 1 Ω
      H37-3 (IN) - H76-3 (ETM) Always Below 1 Ω
      H37-4 (+) - Body ground Always 10 kΩ or higher
      H37-3 (IN) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Remove the STRG HTR relay (steering heater relay) from the No. 2 engine room relay block.

    2. Disconnect the H76 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 - H76-4 (BHT) Always Below 1 Ω
      5 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. CHECK HARNESS AND CONNECTOR (STEERING HEATER SWITCH (COMBINATION SWITCH ASSEMBLY) POWER SOURCE)


    1. Disconnect the H37 steering heater switch (combination switch assembly) connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      H37-9 (IG) - Body ground Power switch on (IG) 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Remove the STRG HTR relay (steering heater 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 Power 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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Disconnect the H76 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
      H76-2 (EHT) - Body ground Always Below 1 Ω

    OK

    REPLACE STEERING WHEEL HEATER CONTROL ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR