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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Body & Frame >> Seats >> Seat Heater System - Diagnostic Codes & Symptom Tests >> Seat Heater System >> Seat Heater for Rear Right Seat does not Operate [11/2023 - ] >> Procedure

Seat Heater for Rear Right Seat does not Operate [11/2023 - ]: Procedure

  1. PERFORM ACTIVE TEST USING GTS 
    1. Perform the Active Test according to the display on the GTS.

      Body Electrical > Air Conditioner > Active Test 

      Tester Display Measurement Item Control Range Diagnostic Note
      Rear Right Seat Heater Rear seat RH side seat heater operation OFF or ON -

      Body Electrical > Air Conditioner > Active Test 

      Tester Display
      Rear Right Seat Heater

      OK

      Rear seat RH side seat heater operates normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO AIR CONDITIONING SYSTEM 

    for HV Model: Refer to HOW TO PROCEED WITH TROUBLESHOOTING [11/2023 - ]

    for Gasoline Model: Refer to HOW TO PROCEED WITH TROUBLESHOOTING [11/2023 - ]

    Result: 

    NG 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (POWER SUPPLY - SEAT HEATER CONTROL SUB-ASSEMBLY RH) 
    1. Disconnect the f4 seat heater control sub-assembly RH connector.
      GTY843601Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Seat Heater Control Sub-assembly RH)
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      f4-1 (+B1) - Body ground Ignition switch ON 11 to 14 V
      f4-1 (+B1) - Body ground Ignition switch off Below 1 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  9

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - SEAT HEATER CONTROL SUB-ASSEMBLY RH) 
    1. Disconnect the H64 air conditioning amplifier assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      H64-23 (SM2R) - f4-5 (SWR) Always Below 1 Ω
      H64-23 (SM2R) or f4-5 (SWR) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (SEAT HEATER CONTROL SUB-ASSEMBLY RH - REAR SEAT CUSHION HEATER RH (SEAT HEATER ASSEMBLY) AND BODY GROUND) 
    1. Disconnect the f1 rear seat cushion heater RH (seat heater assembly) connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      f4-7 (HTR1) - f1-1 Always Below 1 Ω
      f4-7 (HTR1) or f1-1 - Body ground Always 10 kΩ or higher
      f4-10 (E) - f1-3 Always Below 1 Ω
      f4-10 (E) or f1-3 - Body ground Always 10 kΩ or higher
      f1-4 - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  5

  5. INSPECT REAR SEAT CUSHION HEATER RH (SEAT HEATER ASSEMBLY) 

    for Captain Seat Type: Refer to INSPECTION [12/2019 - ]

    for 60/40 Split Seat Type RH Side: Refer to INSPECTION [12/2019 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE REAR SEAT CUSHION HEATER RH (SEAT HEATER ASSEMBLY) 

    for Captain Seat Type: Refer to REMOVAL [12/2019 - ]

    for 60/40 Split Seat Type RH Side: Refer to REMOVAL [12/2019 - ]

    Result: 

    OK 

    See step  6

  6. INSPECT REAR SEATBACK HEATER RH (SEAT HEATER ASSEMBLY) 

    for Captain Seat Type: Refer to INSPECTION [12/2019 - ]

    for 60/40 Split Seat Type RH Side: Refer to INSPECTION [12/2019 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE REAR SEATBACK HEATER RH (SEAT HEATER ASSEMBLY) 

    for Captain Seat Type: Refer to REMOVAL [12/2019 - ]

    for 60/40 Split Seat Type RH Side: Refer to REMOVAL [12/2019 - ]

    Result: 

    OK 

    See step  7

  7. REPLACE SEAT HEATER CONTROL SUB-ASSEMBLY RH 
    1. Temporarily replace the seat heater control sub-assembly RH with a new or known good one.

      Refer to REMOVAL [11/2023 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

  8. CHECK REAR SEAT HEATER OPERATION 
    1. Check the rear seat RH side seat heater operation.

      Refer to OPERATION CHECK [12/2019 - ]

      OK

      Rear seat RH side seat heater operates normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    END (SEAT HEATER CONTROL SUB-ASSEMBLY RH WAS DEFECTIVE) 

    Result: 

    NG 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [11/2023 - ] 

  9. INSPECT S/HTR R/R RELAY 

    Refer to ON-VEHICLE INSPECTION [12/2019 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE S/HTR R/R RELAY 

    Result: 

    OK 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (POWER SUPPLY - S/HTR R/R RELAY) 
    1. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      S/HTR R/R relay holder terminal 1 - Body ground Ignition switch ON 11 V to 14 V
      S/HTR R/R relay holder terminal 1 - Body ground Ignition switch off Below 1 V
      S/HTR R/R relay holder terminal 3 - Body ground Ignition switch off 11 V to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  11

  11. CHECK HARNESS AND CONNECTOR (S/HTR R/R RELAY - SEAT HEATER CONTROL SUB-ASSEMBLY RH) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      S/HTR R/R relay holder terminal 5 - f4-1 (+B1) Always Below 1 Ω
      S/HTR R/R relay holder terminal 5 or f4-1 (+B1) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  12

  12. CHECK HARNESS AND CONNECTOR (S/HTR R/R RELAY - BODY GROUND) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      S/HTR R/R relay holder terminal 2 - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR