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

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 Left Seat Heater	Rear seat LH side seat heater operation	OFF or ON	-

   Body Electrical > Air Conditioner > Active Test 

   Tester Display
   Rear Left Seat Heater

   OK

   Rear seat LH 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

1. Disconnect the f7 seat heater control sub-assembly LH connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Seat Heater Control Sub-assembly LH)

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   f7-1 (+B1) - Body ground	Ignition switch ON	11 to 14 V
   f7-1 (+B1) - Body ground	Ignition switch off	Below 1 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  9

Result: 

OK 

See step  3

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
   H64-24 (SM2L) - f7-5 (SWR)	Always	Below 1 Ω
   H64-24 (SM2L) or f7-5 (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

1. Disconnect the f5 rear seat cushion heater LH (seat heater assembly) connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   f7-7 (HTR1) - f5-1	Always	Below 1 Ω
   f7-7 (HTR1) or f5-1 - Body ground	Always	10 kΩ or higher
   f7-10 (E) - f5-3	Always	Below 1 Ω
   f7-10 (E) or f5-3 - Body ground	Always	10 kΩ or higher
   f5-4 - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  5

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

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

Result

Result: 

NG 

REPLACE REAR SEAT CUSHION HEATER LH (SEAT HEATER ASSEMBLY) 

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

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

Result: 

OK 

See step  6

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

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

Result

Result: 

NG 

REPLACE REAR SEATBACK HEATER LH (SEAT HEATER ASSEMBLY) 

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

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

Result: 

OK 

See step  7

1. Temporarily replace the seat heater control sub-assembly LH with a new or known good one.

   Refer to REMOVAL [11/2023 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  8

1. Check the rear seat LH side seat heater operation.

   Refer to OPERATION CHECK [12/2019 - ]

   OK

   Rear seat LH side seat heater operates normally.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

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

Result: 

NG 

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

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

Result

Result: 

NG 

REPLACE S/HTR R/L RELAY 

Result: 

OK 

See step  10

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

   Standard Voltage

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

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   S/HTR R/L relay holder terminal 5 - f7-1 (+B1)	Always	Below 1 Ω
   S/HTR R/L relay holder terminal 5 or f7-1 (+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

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   S/HTR R/L 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