2003 LEXUS LS430 climate control

CIRCUIT DESCRIPTION
If the climate control seat does not operate, the seat climate control blower (climate control ECU) or the wire
harness may be malfunctioning.
WIRE DIAGRAM
Fig. 58: Climate Control System Does Not Operate On Passenger Side
- Wire Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.INSPECT FUSE (P S/HTR)
a. Remove the P S/HTR fuse from the driver side J/B.
b. Measure the resistance of the relay.
Standard: Below 1 ohms
NG: REPLACE FUSE
OK: Go to next step
2.CHECK WIRE HARNESS (SEAT CLIMATE CONTROL BLOWER (CLIMATE CONTROL
ECU) - BATTERY)
a. Disconnect the C21 blower connector.
b. Measure the voltage of the wire harness side connector.
Standard:
TESTER CONNECTION AND SPECIFIED CONDITION
Tester ConnectionConditionSpecified Condition

Fig. 59: Identifying Seat Climate Control Blower Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
OK: Go to next step
3.CHECK WIRE HARNESS (CLIMATE CONTROL BLOWER (CLIMATE CONTROL ECU) -
BODY GROUND)
a. Disconnect the C21 blower connector.
b. Measure the resistance of the wire harness side connector.
Standard:
TESTER CONNECTION AND SPECIFIED CONDITION
C21-7 (IG) - Body groundIgnition switch ON10 to 14 V

Fig. 60: Identifying Seat Climate Control Blower 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)
4.CHECK WIRE HARNESS (PASSENGER SIDE J/B - BATTERY)
a. Disconnect the PJ J/B connector.
b. Measure the voltage of the J/B connector.
Standard:
TESTER CONNECTION AND SPECIFIED CONDITION
Tester ConnectionSpecified Condition
C20-8 (E) - Body groundBelow 1 ohms

Fig. 61: Identifying PJ Passenger Side J/B Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: Go to step 5
OK: REPAIR OR REPLACE HARNESS AND CONNECTOR (PASSENGER SIDE J/B -
CLIMATE CONTROL BLOWER (CLIMATE CONTROL ECU))
5.CHECK WIRE HARNESS (PASSENGER SIDE J/B - BODY GROUND
a. Disconnect the PA and PE J/B connectors.
b. Measure the voltage of the wire harness side connectors.
Tester ConnectionConditionSpecified Condition
PJ-9 - Body groundIgnition switch ON10 to 14 V

CIRCUIT DESCRIPTION
If the climate control seat does not operate, the seat climate control blower (climate control ECU), the climate
control switch or the wire harness may have a malfunction.
WIRE DIAGRAM
Fig. 65: Climate Control System Does Not Operate On Rear Side
- Wire Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE

1.INSPECT FUSE (RR S/HTR)
a. Remove the RR S/HTR fuse from the luggage room J/B.
b. Measure the resistance of the relay.
Standard: Below 1 ohms
NG: REPLACE FUSE
OK: Go to next step
2.CHECK WIRE HARNESS (SEAT CLIMATE CONTROL BLOWER (CLIMATE CONTROL
ECU) - BATTERY)
a. Disconnect the C27 or C29 blower connector.
b. Measure the voltage of the wire harness side connector.
Standard:
Rear LH
TESTER CONNECTION AND SPECIFIED CONDITION
Rear RH
TESTER CONNECTION AND SPECIFIED CONDITION - REAR RH
Tester ConnectionConditionSpecified Condition
C27-10 (IG) - Body groundIgnition switch ON10 to 14 V
Tester ConnectionConditionSpecified Condition
C29-10 (IG) - Body groundIgnition switch ON10 to 14 V

Fig. 66: Identifying Seat Climate Control Blower Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: Go to step 5
OK: Go to next step
3.CHECK WIRE HARNESS (SEAT CLIMATE CONTROL BLOWER (CLIMATE CONTROL
ECU) - BODY GROUND)
a. Disconnect the C27 or C29 blower connector.
b. Measure the resistance of the wire harness side connector.
Standard:
Rear LH
TESTER CONNECTION AND SPECIFIED CONDITION - REAR RH
Tester ConnectionSpecified Condition
C27-11 (GND) - Body groundBelow 1 ohms

Rear RH
TESTER CONNECTION AND SPECIFIED CONDITION - REAR RH
Fig. 67: Identifying Seat Climate Control Blower 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) - BODY GROUND)
a. Disconnect the C27 or C29 blower connector.
b. Measure the resistance of the wire harness side connector.
Tester ConnectionSpecified Condition
C29-11 (GND) - Body groundBelow 1 ohms