2003 LEXUS LS430 air condition

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Standard (Passenger side):
AIR MIX CONTROL SERVOMOTOR - AIR CONDITIONING AMPLIFIER RESISTANCE
(PASSENGER SIDE)
Tester connectionConditionSpecified condition
A36-1 (AMPa1) -A43-6AlwaysBelow 1 ohms
A36-2 (AMPa2) -A43-5AlwaysBelow 1 ohms
A36-3 (AMPa3) -A43-2AlwaysBelow 1 ohms
A36-4 (AMPa4) -A43-1AlwaysBelow 1 ohms
A36-13 (AMPB) - A43-4AlwaysBelow 1 ohms
A36-1 (AMPa1) - Body groundAlways10 kohms or higher
A36-2 (AMPa2) - Body groundAlways10 kohms or higher
A36-3 (AMPa3) - Body groundAlways10 kohms or higher
A36-4 (AMPa4) - Body groundAlways10 kohms or higher
A36-13 (AMPB) - Body groundAlways10 kohms or higher

Fig. 145: Checking Harness And Connector (Air Mix Control Servomotor - Air Conditioning
Amplifier) (Passenger Side)

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS OR / CONNECTOR
OK: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
This is the back-up power source circuit for the A/C amplifier. Power is supplied even when turning the ignition
switch off and is used for diagnostic trouble code memory, etc.
WIRING DIAGRAM
Fig. 146: Back
-Up Power Source Circuit

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.INSPECT RADIO AND RECEIVER ASSY
a. Turn the ignition switch to the ON position.
b. Turn the radio and receiver assy on.
c. Set the radio channels and register them.
d. Turn the ignition switch off.
e. Turn the ignition switch to the ON position.
f. Turn the radio and receiver assy on.
g. Check if the registered memory is deleted or not.
OK:
The registered memory is not deleted.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (DRIVER SIDE J/B - BATTERY)
OK: Go to next step
2.INSPECT FUSE (A/C)
a. Remove the A/C fuse from the driver side J/B.
b. Measure the resistance according to the value (s) in the table below.
Standard:
FUSE (A/C) RESISTANCE
NG: CHECK FOR SHORT IN ALL HARNESSES AND COMPONENTS CONNECTED TO
FAILURE FUSE
Tester itemConditionSpecified condition
A/C fuseAlwaysBelow 1 ohms

Fig. 147: Identifying Location Of Fuse (A/C)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: Go to next step
3.INSPECT AIR CONDITIONING AMPLIFIER (B - BODY GROUND)
a. Remove the A/C amplifier assy and disconnect the connector.
b. Measure the voltage according to the value (s) in the table below.
Standard:
AIR CONDITIONING AMPLIFIER (B - BODY GROUND) VOLTAGE
NG: REPAIR OR REPLACE WIRE HARNESS (AIR CONDITIONING AMPLIFIER -
BATTERY)
Tester connectionConditionSpecified condition
A11-21 (+B) - Body groundAlways10 to 14 V

Fig. 148: Inspecting Air Conditioning Amplifier (B - Body Ground)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS
TABLE
CIRCUIT DESCRIPTION
The main power source is supplied to the A/C amplifier when the ignition switch is turned to the ON position.
The power source supplied is used for operating the A/C amplifier and servomotor, etc.
WIRING DIAGRAM

FUSE (P-IG) RESISTANCE
NG: CHECK FOR SHORT IN ALL HARNESSES AND COMPONENTS CONNECTED TO
FAILURE FUSE
OK: Go to next step
2.INSPECT AIR CONDITIONING AMPLIFIER (IG - GND)
a. Remove the A/C amplifier assy with connectors still connected.
b. Turn the ignition switch to the ON position.
c. Measure the voltage according to the value (s) in the table below.
Standard:
AIR CONDITIONING AMPLIFIER (IG - GND) VOLTAGE
NG: Go to STEP 3
Tester itemConditionSpecified condition
P-IG fuseAlwaysBelow 1 ohms
Tester connectionConditionSpecified condition
A11-9 (IG) - 14-1 (GND)Ignition switch ON10 to 14V

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2a0003[- GND)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS
TABLE
3.CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BATTERY)
(SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
a. Measure the voltage according to the value (s) in the table below.
Standard:
AIR CONDITIONING AMPLIFIER - BATTERY VOLTAGE
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
Tester connectionConditionSpecified condition
A11-9 (IG) - Body groundIgnition switch OFF --> ONBelow 1.0V --> 10 to 14 V