2003 LEXUS LS430 rear seat back

Fig. 26: Identifying Seat Climate Control Blower Connector Terminals And Seat Climate
Controller Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
OK: Go to next step
9.CHECK SEAT HEATER (SEATBACK) (SEE INSPECTION
)
NG: REPLACE REAR SEATBACK PAD
OK: Go to next step
10.INSPECT SEAT HEATER (SEAT CUSHION) (SEE INSPECTION
)
NG: REPLACE SEAT CUSHION PAD
OK: Go to next step
11.CHECK WIRE HARNESS (SEAT CLIMATE CONTROL BLOWER (CLIMATE CONTROL
ECU) - SEAT HEATER)
HINT:
When the indicator of rear left side is blinking, check the rear left side connector. When the indicator of
rear right side is blinking, check the rear right side connector.
a. Disconnect the C28 or C30 blower connector.
b. Disconnect the S60 or S61 heater connector.
c. Measure the resistance of the wire harness side connectors.
Standard:
Rear LH
TESTER CONNECTION AND SPECIFIED CONDITION - REAR LH
Rear RH
TESTER CONNECTION AND SPECIFIED CONDITION - REAR RH
Tester ConnectionSpecified Condition
C28-8 (E) - S60-3 (E)Below 1 ohms
C28-8 (E) - S60-1 (B)10 kohms or higher
C28-18 (B) - S60-1 (B)Below 1 ohms
C28-18 (B) - S60-3 (E)10 kohms or higher

Fig. 27: Identifying Seat Climate Control Blower Connector Terminals And Seat Heater Connector
Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
OK: Go to next step
12.INSPECT SEAT CLIMATE CONTROL BLOWER (FAN MOTOR OF SEATBACK) (SEE
INSPECTION
)
NG: REPLACE SEAT CLIMATE CONTROL BLOWER (SEATBACK)
OK: Go to next step
13.CHECK WIRE HARNESS (SEAT CLIMATE CONTROL BLOWER (CLIMATE CONTROL
ECU) - SEAT CLIMATE FAN MOTOR)
HINT:
When the indicator of rear left side is blinking, check the rear left side connector. When the indicator of
rear right side is blinking, check the rear right side connector.
a. Disconnect the C27 or C29 blower connector.
b. Disconnect the S56 or S58 motor connector.
c. Measure the resistance of the wire harness side connectors.
Standard:
Rear LH
TESTER CONNECTION AND SPECIFIED CONDITION - REAR LH
Rear RH
TESTER CONNECTION AND SPECIFIED CONDITION - REAR RH
Tester ConnectionSpecified Condition
C27-3 (BBS) - S56-3 (BBS)Below 1 ohms
C27-3 (BBS) - S56-2 (BFB(+))10 kohms or higher
C27-2 (BFB+) - S56-2 (BFB(+))Below 1 ohms
C27-2 (BFB+) - S56-3 (BBS)10 kohms or higher
Tester ConnectionSpecified Condition
C29-3 (BBS) - S58-3 (BBS)Below 1 ohms
C29-3 (BBS) - S58-2 (BFB(+))10 kohms or higher
C29-2 (BFB+) - S58-2 (BFB(+))Below 1 ohms

Fig. 39: Identifying Seat Climate Control Blower Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPLACE SEAT CLIMATE CONTROL CONTROLLER (CLIMATE CONTROL ECU)
OK: Go to next step
11.INSPECT SEAT CLIMATE CONTROL CONTROLLER (THERMISTOR OF SEATBACK)
(SEE INSPECTION
)
NG: REPLACE SEAT CLIMATE CONTROL CONTROLLER
OK: Go to next step
12.CHECK WIRE HARNESS (SEAT CLIMATE CONTROL BLOWER (CLIMATE CONTROL
ECU) - SEAT CLIMATE CONTROLLER)
HINT:
When the rear LH indicator is blinking, check the rear LH side connector. When the rear RH indicator is
blinking, check the rear right RH side connector.

RESULT REFERENCE
B: Go to step 5
A: Go to next step
2.INSPECT FRONT SEAT HEATER SWITCH (THERMISTOR OF SEATBACK) (SEE
INSPECTION
)
NG: REPLACE FRONT SEAT HEATER SWITCH
OK: Go to next step
3.CHECK WIRE HARNESS (SEAT CLIMATE CONTROL BLOWER (CLIMATE CONTROL
ECU) - SEAT CLIMATE CONTROLLER (SEATBACK))
HINT:
When the driver side indicator is blinking, check the driver side connector. When the passenger side
indicator is blinking, check the passenger side connector.
a. Disconnect the C20 or C21 blower connector.
b. Disconnect the S34 or S35 controller connector.
c. Measure the resistance of the wire harness side connectors.
Standard:
Driver side
TESTER CONNECTION AND SPECIFIED CONDITION - DRIVER SIDE
Passenger side
TESTER CONNECTION AND SPECIFIED CONDITION - PASSENGER SIDE
ResultProceed to
Front climate control switch indicator is blinkingA
Rear climate control switch indicator is blinkingB
Tester ConnectionSpecified Condition
C20-3 (TBS) - S34-2 (TBS)Below 1 ohms
C20-4 (TB5) - S34-3 (TB5)Below 1 ohms
Tester ConnectionSpecified Condition
C21-3 (TBS) - S35-2 (TBS)Below 1 ohms
C21-4 (TB5) - S35-3 (TB5)Below 1 ohms

Fig. 47: Identifying Seat Climate Controller Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPLACE FRONT SEAT HEATER SWITCH
OK: REPLACE SEAT CLIMATE CONTROL CONTROLLER
5.INSPECT REAR SEAT HEATER SWITCH (THERMISTOR OF SEATBACK) (SEE
INSPECTION
)
NG: REPLACE FRONT SEAT HEATER SWITCH
OK: Go to next step
6.CHECK WIRE HARNESS (SEAT CLIMATE CONTROL BLOWER (CLIMATE CONTROL
ECU) - SEAT CLIMATE CONTROLLER)
HINT:

Fig. 88: Identifying Seat Climate Controller RH Connector Terminals (Rear Seat Cushion)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
i.INSPECT SEAT CLIMATE CONTROL BLOWER LH (REAR SEATBACK)
a. Connect the battery's positive (+) lead to terminals 3 (BBS) and 4 (BFB-), and the negative (-
) lead to terminal 2 (BFB+). Check that the blower fan motor operates smoothly.
If the result is not as specified, replace the blower.

Fig. 89: Inspecting Seat Climate Control Blower LH (Rear Seatback)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
j.INSPECT SEAT CLIMATE CONTROL BLOWER RH (REAR SEATBACK)
a. Connect the battery's positive (+) lead to terminals 3 (BBS) and 4 (BFB-), and the negative (-
) lead to terminal 2 (BFB+). Check that the blower fan motor operates smoothly.
If the result is not as specified, replace the blower.

Fig. 90: Inspecting Seat Climate Control Blower RH (Rear Seatback)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
k.INSPECT SEAT CLIMATE CONTROLLER LH (REAR SEATBACK)
a. Measure the resistance between the terminals when the switch is operated.
Standard:
TESTER CONNECTION AND SPECIFIED CONDITION
If the result is not as specified, replace the controller.
b. Measure the thermistor resistance between the terminals
Standard:
TESTER CONNECTION AND SPECIFIED CONDITION
Tester ConnectionConditionSpecified Condition
4 (TDB-) - 5 (TDB+)AlwaysBelow 1 ohms
Tester ConnectionConditionSpecified Condition