Seat Heater for Rear Left Seat does not Operate [11/2020 - 12/2023]: Procedure

1. Perform the Active Test according to the display on the GTS.

   Refer to DATA LIST / ACTIVE TEST [11/2020 - 12/2023]

   Body Electrical > Air Conditioner > Active Test 

   Tester Display	Measurement Item	Control Range	Diagnostic Note
   Rear Left Seat Heater	Rear left seat heater operation	OFF/ON	-

   Body Electrical > Air Conditioner > Active Test 

   Tester Display
   Rear Left Seat Heater

   OK

   Rear left seat heater operates normally.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  4

Result: 

OK 

See step  2

1. Replace the air conditioner amplifier assembly with a new one or known good one.

   Refer to REMOVAL [11/2020 - ]

   Result

   Proceed to
   OK

Result: 

OK 

See step  3

1. Check the rear seat heater operation.

   Refer to OPERATION CHECK [11/2020 - ]

   OK

   Rear seat heater operates normally.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

END (AIR CONDITIONING CONTROL ASSEMBLY WAS DEFECTIVE) 

Result: 

NG 

REPLACE COOLER CONTROL SWITCH ASSEMBLY. Refer to  REMOVAL [11/2020 - ] 

1. Disconnect the M3 rear seat heater control sub-assembly LH connector.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   M3-1 (B1) - Body ground	Ignition switch ON	11 to 14 V
   M3-1 (B1) - Body ground	Ignition switch off	Below 1 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  5

1. Disconnect the D79 air conditioning amplifier assembly connector.
2. Disconnect the M3 seat heater control sub-assembly LH connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   D79-24 (SM2L) - M3-5 (SWR)	Always	Below 1 Ω
   D79-24 (SM2L) or M3-5 (SWR) - Other terminals and body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  6

1. Disconnect the M1 seatback heater assembly LH connector.
2. Disconnect the M3 rear seat heater control sub-assembly LH connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   M1-4 - M3-10(E)	Always	Below 1 Ω
   M1-1 - M3-7(HTR)	Always	Below 1 Ω
   M1-4 or M3-10 (E) - Other terminals and body ground	Always	10 kΩ or higher
   M1-1 or M3-7(HTR) - Other terminals and body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  7

1. Disconnect the M1 seatback heater assembly LH connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   M1-5 - Body ground	Always	Below 1 Ω
   M1-5 - Other terminals and body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  8

Refer to INSPECTION [11/2020 - ]

Result

Result: 

NG 

REPLACE SEATBACK HEATER ASSEMBLY LH. Refer to  REMOVAL [11/2020 - ] 

Result: 

OK 

See step  9

Refer to INSPECTION [11/2020 - ]

Result

Result: 

NG 

REPLACE REAR SEAT CUSHION HEATER ASSEMBLY LH. Refer to  REMOVAL [11/2020 - ] 

Result: 

OK 

See step  10

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

   Refer to REMOVAL [11/2020 - ]

   Result

   Proceed to
   OK

Result: 

OK 

See step  11

1. Check the rear seat heater operation.

   Refer to OPERATION CHECK [11/2020 - ]

   OK

   Rear seat heater operates normally.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

END (REAR SEAT HEATER CONTROL ECU RH WAS DEFECTIVE) 

Result: 

NG 

REPLACE AIR CONDITIONING CONTROL ASSEMBLY. Refer to  REMOVAL [11/2020 - ]