LEXUS LS430 2003 Factory Repair Manual

C25-5 (MSNUT) - Body groundAlways10 kohms or higher
C25-1 (VZ) - Body groundAlways10 kohms or higher
C25-2 (GND) - Body groundAlwaysBelow 1 ohms

Fig. 131: Checking Harness And Connector (Cool Air Bypass Servomotor - Air Conditioning

Amplifier)
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 circuit controls the amount of the coolant flowing to the heater core by a signal from the A/C amplifier,
and adjusts the temperature at the air outlets.
WIRING DIAGRAM
Fig. 132: Water Valve Control Servomotor Circuit

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

INSPECTION PROCEDURE
1.PERFORM ACTUATOR CHECK

a. Warm up the engine.
b. Set the actuator check mode (SEE ACTUATOR CHECK
).
c. Press the driver temperature up switch, and change to STEP operation.
d. Press the driver temperature up switch, and check the operation of water valve.
Fig. 133: Checking Actuator

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
DISPLAY CODE - AIR FLOW LEVER POSITION
Display codeAir flow lever position
0SHUT
1SHUT
2SHUT
3OPEN
4OPEN
5OPEN
6OPEN

OK:
Water valve lever changes in accordance with each display code.
NG: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT
)
OK: Go to next step
2.INSPECT WATER VALVE SERVOMOTOR
a. Remove the water valve servomotor.
b. Connect the positive (+) lead from the battery to terminal 3 and negative (-) lead to terminal 1, then
check that the lever turns to the "OPEN" position smoothly.
c. Connect the positive (+) lead from the battery to terminal 3 and negative (-) lead to terminal 2, then
check that the lever turns to the "SHUT" position smoothly.
Fig. 134: Inspecting Water Valve Servomotor

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
7OPEN
8OPEN
9OPEN

NG: REPLACE WATER VALVE SERVOMOTOR
OK: Go to next step
3.CHECK HARNESS AND CONNECTOR (WATER VALVE SERVOMOTOR - AIR
CONDITIONING AMPLIFIER) (SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
a. Measure the resistance according to the value (s) in the table below.
Standard:
WATER VALVE SERVOMOTOR - AIR CONDITIONING AMPLIFIER RESISTANCE
Tester connectionConditionSpecified condition
A37-15 (WVO) - W4-1 (OPEN)AlwaysBelow 1 ohms
A37-7 (WVS) - W4-2 (SHUT)AlwaysBelow 1 ohms
A37-14 (WVIG) - W4-3 (+)AlwaysBelow 1 ohms
A37-15 (WVO) - Body groundAlways10 kohms or higher
A37-7 (WVS) - Body groundAlways10 kohms or higher
A37-14 (WVIG) - Body groundAlways10 kohms or higher

Fig. 135: Checking Harness And Connector (Water Valve Servomotor - Air Conditioning

Amplifier)
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 circuit turns the servomotor and changes each damper position by receiving the signals from the A/C
amplifier assy. When the AUTO switch is on, the A/C amplifier changes the mode between "FACE", "BI-
LEVEL" and "FOOT" following the temperature setting.
WIRING DIAGRAM

Fig. 136: Air Vent Mode Damper Control Servomotor Circuit
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.PERFORM ACTUATOR CHECK

a. Warm up the engine.
b. Set the actuator check mode (see ACTUATOR CHECK).

c. Press the driver temperature up switch, and change to STEP operation.
d. Press the driver temperature up switch, and check the air flow mode by hand.
DISPLAY CODE - AIR FLOW POSITION
OK:
Air flow position changes in accordance with each display code.
NG: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT
)
OK: Go to next step
2.INSPECT AIR VENT MODE CONTROL SERVOMOTOR
a. Remove the vent mode control servomotor.
b. Measure resistance according to the value (s) in the table below:
Standard: (Driver side)
AIR VENT MODE CONTROL SERVOMOTOR (DRIVER SIDE) RESISTANCE
Display codeAir flow position
0FACE
1FACE
2FACE
3FACE
4BI-LEVEL
5BI-LEVEL
6FOOT
7FOOT
8FOOT/DEF
9DEF
Tester connectionConditionSpecified condition
A44-1 (AODr1) -A44-4 (AODB)Always24.3 to 26.3 ohms
A44-2 (AODr2) -A44-4 (AODB)Always24.3 to 26.3 ohms
A44-5 (AODr3) -A44-4 (AODB)Always24.3 to 26.3
A44-6 (AODr4) -A44-4 (AODB)Always24.3 to 26.3