2003 LEXUS LS430 climate control

Controller Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
OK: Go to next step
13.INSPECT SEAT CLIMATE CONTROL CONTROLLER (THERMISTOR OF SEAT CUSHION)
(SEE INSPECTION
)
NG: REPLACE SEAT CLIMATE CONTROL CONTROLLER
OK: Go to next step
14.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.
a. Disconnect the C28 or C30 blower connector.
b. Disconnect the S53 or S55 controller 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
C28-15 (TCS) - S53-2 (TCS)Below 1 ohms
C28-6 (TC5) - S53-3 (TC5)Below 1 ohms
Tester ConnectionSpecified Condition
C30-15 (TCS) - S55-2 (TCS)Below 1 ohms
C30-6 (TC5) - S55-3 (TC5)Below 1 ohms

Fig. 41: 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
15.INSPECT SEAT HEATER (THERMISTOR)
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.
a. Disconnect the S60 or S61 heater connector.
b. Check the resistance between the terminals of the heater.
Standard:
Rear LH
TESTER CONNECTION AND SPECIFIED CONDITION - REAR LH
Rear RH
TESTER CONNECTION AND SPECIFIED CONDITION - REAR RH
Tester ConnectionAmbient TemperatureSpecified Condition
S60-2 (H5) - S60-4 (HS)10°C (50°F)Approx. 3.7 kohms
S60-2 (H5) - S60-4 (HS)25°C (77°F)Approx. 2 ohms
S60-2 (H5) - S60-4 (HS)30°C (86°F)Approx. 1.7 ohms
Tester ConnectionAmbient TemperatureSpecified Condition
S61-2 (H5) - S61-4 (HS)10°C (50°F)Approx. 3.7 kohms
S61-2 (H5) - S61-4 (HS)25°C (77°F)Approx. 2 ohms
S61-2 (H5) - S61-4 (HS)30°C (86°F)Approx. 1.7 ohms

Fig. 42: Identifying Seat Heater Connector Terminals (Thermistor)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPLACE SEAT HEATER
OK: Go to next step
16.CHECK WIRE HARNESS (SEAT CLIMATE CONTROL BLOWER (CLIMATE CONTROL
ECU) - SEAT HEATER)
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.
a. Disconnect the C28 or C30 blower connector.

Fig. 43: 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: REPLACE SEAT CLIMATE CONTROL BLOWER (CLIMATE CONTROL ECU)
CIRCUIT DESCRIPTION
The thermistor circuit inside the seat climate controller or the thermistor circuit of the rear seat heater may
become open or short circuit, or the thermistor's output values may not change because it is damaged. If these
situations occur, output from the Peltier element, fan motor, rear seat heater, idle-up signal (not including the
front passenger side) will be stopped and the indicator illuminates according to blinking pattern 4.
WIRING DIAGRAM

Fig. 44: Climate Control Does Not Operate (Blinking Pattern 4) Wiring Diagram (1 Of 2)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

Fig. 45: Climate Control Does Not Operate (Blinking Pattern 4) Wiring Diagram (2 Of 2)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.CHECK SEAT HEATER (INDICATOR)
a. Check that the climate control indicator is blinking.
Result:

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. 46: 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
4.CHECK WIRE HARNESS (SEAT CLIMATE CONTROL BLOWER (CLIMATE CONTROL
ECU) - SEAT CLIMATE CONTROLLER)
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 S48 or S49 controller connector.
b. Measure the resistance of the wire harness side connector.
Standard:
Driver side
TESTER CONNECTION AND SPECIFIED CONDITION - DRIVER SIDE
Passenger side
TESTER CONNECTION AND SPECIFIED CONDITION - PASSENGER SIDE
HINT:
As the temperature increases, the resistance decreases.
Tester ConnectionAmbient TemperatureSpecified Condition
S48-2 (TC5) - S48-1 (TCS)10°C (50°F)Approx. 3.7 kohms
S48-2 (TC5) - S48-1 (TCS)25°C (77°F)Approx. 2 kohms
S48-2 (TC5) - S48-1 (TCS)30°C (86°F)Approx. 1.7 kohms
Tester ConnectionAmbient TemperatureSpecified Condition
S49-2 (TC5) - S49-1 (TCS)10°C (50°F)Approx. 3.7 kohms
S49-2 (TC5) - S49-1 (TCS)25°C (77°F)Approx. 2 kohms
S49-2 (TC5) - S49-1 (TCS)30°C (86°F)Approx. 1.7 kohms