2003 LEXUS LS430 Identifying ac

2.CHECK SEAT CLIMATE CONTROL BLOWER RH (FR) (CLIMATE CONTROL ECU)
Fig. 9: Identifying Terminals Of Climate Control ECU
- RH (FR)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
a. Disconnect the C21 and S49 blower connectors.
b. Measure the voltage and resistance of the wire harness side connectors.
Standard:
TERMINAL DESCRIPTION AND SPECIFIED CONDITION
Symbols
(Terminal
No.)Wiring
ColorTerminal DescriptionConditionSpecified
Condition
E (C21-8) -
Body groundW-B -
Body
ground
GroundAlwaysBelow 1 ohms
IG (C21-7) -
Body groundG - Body
groundPower sourceIgnition switch ON10 to 14 V
V5 (C21-13) -
VG (C21-9)BR-Y -
V-RPower source for
volume switchAlways5 kohms
VS (C21-12) -
VG (21-9)B-O - V-
RVolume switch signalTurn volume switch: Max.
COOL --> Max. WARM0 ohms --> 5
kohms
TB5 (C21-4) - Seatback temperature Turn volume switch: 10°C -->
Approx. 3.7
kohms -->

Fig. 10: Identifying Terminals Of Climate Control ECU - LH (RR)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
a. Disconnect the C27 and C28 blower connectors.
b. Measure the voltage and resistance of the wire harness side connectors.
Standard:
TERMINAL DESCRIPTION AND SPECIFIED CONDITION
If the result is not as specified, there ma
y be a malfunction on the wire harness side.
Symbols
(Terminal No.)Wiring
ColorTerminal
DescriptionConditionSpecified Condition
GND (C27-11) -
Body groundW-B -
Body
ground
GroundAlwaysBelow 1 ohms
IG (C27-10) -
Body groundR-B - Body
groundPower sourceIgnition switch ON10 to 14 V
SW (C27-8) -
Body groundL - Body
groundClimate control
switchTurn the climate control
switch ONBelow 1 ohms
V5 (C27-18) -
VG (C27-16)Y-R - PVolume switchAlways5 kohms
VS (C27-17) -
VG (C27-16)GR-R - PVolume switch
signalRear left volume switch:
Max. COOL --> Max.
WARM
0 ohms --> 5 kohms
TB5 (C28-7) -
TBS (C28-16)G-Y - RSeatback
temperatureSeatback temperature: 10°
C --> 30°C (50°F --> 86°F)Approx. 3.7 kohms -
-> Approx. 1.7
kohms
H5 (C28-5) - HS
(C28-14)L-B - Y-RSeat cushion
temperature sensorSeat cushion temperature:
10°C --> 30°C (50°F -->
86°F)Approx. 3.7 kohms -
-> Approx. 1.7
kohms
TC5 (C28-6) -
TCS (C28-15)BR-R - P-
BHeater
temperature sensorHeater temperature: 10°C -
-> 30°C (50°F --> 86°F)Approx. 3.7 kohms -
-> Approx. 1.7
kohms

HINT:
*: For vehicles with a front seat climate control system
If the result is not as specified, the ECU may have a malfunction.
4.SEAT CLIMATE CONTROL BLOWER RH (RR) (CLIMATE CONTROL ECU)
Fig. 11: Identifying Terminals Of Climate Control ECU
- RH (RR)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
a. Disconnect the C29 and C30 blower connectors.
b. Measure the voltage and resistance of the wire harness side connector.
Standard:
TERMINAL DESCRIPTION AND SPECIFIED CONDITION
> Max. WARM
E (C28-8) - Body
groundB-R - Body
groundGround for seat heaterAlwaysBelow 1 V
IDL (C28-3) -
Body groundG - Body
groundEngine idle-up signal
Ignition switch: ON Turn
climate control switch: OFF --
> ON10 to 14 V --
> 0 V
Symbols
(Terminal No.)Wiring
ColorTerminal
DescriptionConditionSpecified Condition
GND (C29-11) -
Body groundW-B -
Body
ground
GroundAlwaysBelow 1 ohms
IG (C29-10) -
Body groundR-B - Body
groundPower sourceIgnition switch ON10 to 14 V
SW (C29-8) -
Body groundV-R -
Body Climate control
switchTurn climate control
switch ONBelow 1 ohms

Fig. 13: Identifying DLC3 Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
TERMINAL DESCRIPTION AND SPECIFIED CONDITION
HINT:
Connect the cable of the hand-held tester (with CAN VIM) to the DLC3, turn the ignition switch ON and
attempt to use the hand-held tester. If the screen displays the message UNABLE TO CONNECT TO
VEHICLE, there is a problem either with the vehicle or with the tester.
If communication is normal when the tester is connected to another vehicle, inspect the DLC3 on
the original vehicle.
If communication is still impossible when the tester is connected to another vehicle, the problem is
probably in the tester itself. Consult the Service Department listed in the tester's instruction manual.
Symbols (Terminals No.)Terminal DescriptionConditionSpecified condition
SIL (7) - SG (5)Bus "+" lineDuring transmissionPulse generation
CG (4) - Body groundChassis groundAlwaysBelow 1 ohms
SG (5) - Body groundSignal groundAlwaysBelow 1 ohms
BAT (16) - Body groundBattery positiveAlways11 to 14 V

Fig. 15: Climate Control Switch Blinking Patterns
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
HINT:
After identifying the blinking pattern, troubleshoot according to the flow chart below.
Fig. 16: Diagnostic Trouble Code Chart

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
CIRCUIT DESCRIPTION
As a result of a short circuit, overcurrent may occur in the Peltier element of the seat climate controller, fan
motor or rear seat heater. If this happens, output from the Peltier element, fan motor, rear seat heater and idle-up
signal (not including the front passenger side) will be stopped and the indicator illuminates according to
blinking pattern 1.
WIRING DIAGRAM

Fig. 21: Identifying Seat Climate Control Blower Connector And Seat Climate Controller

Fig. 24: 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
7.CHECK SEAT CLIMATE CONTROL CONTROLLER (SEAT CUSHION)
HINT:
When the rear LH indicator is blinking, check the rear LH connector. When the rear RH indicator is
blinking, check the rear RH connector.
a. Disconnect the S53 or S55 blower connector.
b. Connect the wire harness to terminal 5 (TDC+) and 4 (TDC-) of the wire harness side connector, as
shown in the illustration.
c. Turn the ignition switch ON.
d. Turn the climate control switch ON, and then check that the climate control indicator turns off.
OK: The indicator turns off

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