engine coolant LEXUS GS400 2000 Service Repair Manual

AC0WA±01
I03811
Smog Ventilation
Sensor
No. 2 Cooling Fan Relay
(Marking: FAN NO.2) No. 3 Cooling Fan Relay
(Marking: FAN NO.3)
CompressorMagnetic Clutch Relay
(Marking A/C COMP)
Condenser
Ambient Temperature Sensor Condenser Fan
Engine Coolant Temperature
(ECT) Switch
Air Inlet Servomotor
Blower Motor
Air Outlet Servomotor A/C Amplifier
EvaporatorSolar Sensor A/C Control Assembly
Electrical Multi Vision
(Built in A/C Control Assembly)
Expansion Valve
Air Refiner Filter
Blower Motor Control
Relay Evaporator Temperature
Sensor
Heater Radiator
Air Mix Servomotor
(Driver Side) Air Mix Servomotor
(Passenger Side)Room Temperature
Sensor
± AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC±13
2698 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
LOCATION

AC0WK±01
I02360
I02361
AC±24
± AIR CONDITIONINGAIR CONDITIONING UNIT
2709 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
REMOVAL
1. DISCHARGE REFRIGERANT FROM REFRIGERATION
SYSTEM
HINT:
At the time of installation, please refer to the following item.
Evacuate air from refrigeration system.
Charge system with refrigerant and inspect for leakage of refrig-
erant.
Specified amount: 600 ± 50 g (21.16 ± 1.76 oz.)
2. DRAIN ENGINE COOLANT FROM RADIATOR
HINT:
It is not necessary to drain out all coolant.
3. DISCONNECT LIQUID TUBE AND SUCTION HOSE
FROM A/C UNIT
Remove the bolt and slide the plate, then disconnect the both
tubes.
Torque: 10 N´m (100 kgf´cm, 7 ft´lbf)
NOTICE:
Cap the open fittings immediately to keep moisture or dirt
out of the system.
HINT:
At the time of installation, please refer to the following item.
Lubricate 2 new O±rings with compressor oil and install them
to the tubes.
4. DISCONNECT WATER HOSES FROM HEATER RA-
DIATOR PIPES
(a) Grips the claws of the hose clip and slide the hose clip
along the hose.
(b) Disconnect the water hose.

AC0Y2±01
I03743
1 2 AC±80
± AIR CONDITIONINGCONDENSER FAN
2765 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
CONDENSER FAN
ON±VEHICLE INSPECTION
1. INSPECT CONDENSER FAN OPERATION
Inspect the fan operation, as shown in the chart below.
Test conditions:

Ignition switch ON

Blower speed control switch position ºHIº

Temperature control dial at ºMAX. COOLº

Install manifold gauge setº

A/C switch ON
ConditionFan operation (Fan speed)
Engine coolant temperature
91°C (196 °F) or belowRotate (Low speed)
Engine coolant temperature
100°C (212 °F) or aboveRotate (High speed)
Refrigerant pressure is less than
1,520 kPa (15.5 kgf´cm2, 220 psi)Rotate (Low speed)
Refrigerant pressure is 1,520 kPa
(15.5 kgf´cm2, 220 psi) or aboveRotate (High speed)
If operation is not as specified, proceed to the next inspection.
2. INSPECT CONDENSER FAN MOTOR OPERATION
(a) Disconnect the fan connector.
(b) Connect the positive (+) lead from the battery to terminal
2 and negative (±) lead to terminal 1 then check that motor
operations smoothly.

If operation is not as specified, replace the fan mo-
tor.

If operation is as specified, check the pressure
switch, cooling fan relays and engine coolant temp.
switch.

AC0Y4±01
AC±82
± AIR CONDITIONINGCONDENSER FAN
2767 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
REMOVAL
1. DRAIN ENGINE COOLANT FROM RADIATOR
HINT:
It is not necessary to drain out all coolant.
2. REMOVE THESE PARTS:
(a) Air cleaner duct
(b) Air cleaner assembly
(c) Radiator reservoir tank cap
3. DISCONNECT THESE PARTS:
(a) Upper radiator hose
(b) Reservoir hose
4. REMOVE COOLING FAN
(a) Disconnect the connectors.
(b) Remove the 6 bolts cooling fan.

AC0XX±01
I05028
AC±92
± AIR CONDITIONINGENGINE COOLANT TEMPERATURE (ECT) SWITCH
2777 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
ENGINE COOLANT
TEMPERATURE (ECT) SWITCH
REMOVAL
1. REMOVE ENGINE UNDER COVER
2. DRAIN ENGINE COOLANT FROM RADIATOR
HINT:
It is not necessary to drain out all coolant
3. REMOVE ECT SWITCH
(a) Disconnect the connector.
(b) Remove the ECT switch.
Torque: 7.4 N´m (75 kgf´cm, 65 in.´lbf)
(c) Remove the O±ring from ECT switch.
HINT:
At the time of installation, please refer to the following item.
Lubricate a new O±ring with soapy water and install the switch.

AC0XY±01
P01924
Ohmmeter
± AIR CONDITIONINGENGINE COOLANT TEMPERATURE (ECT) SWITCH
AC±93
2778 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
INSPECT ECT SWITCH
(a) Using an ohmmeter, check that no continuity exists be-
tween the terminals when the coolant temperature is
above 100 °C (212 °F).
If continuity exists, replace the switch.
(b) Using an ohmmeter, check that continuity exists between
the terminals when the coolant temperature is below
91 °C (196 °F).
If there no continuity exists, replace the switch.

AC0XZ±01
AC±94
± AIR CONDITIONINGENGINE COOLANT TEMPERATURE (ECT) SWITCH
2779 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSTALLATION
Installation is in the reverse order of removal (See page AC±92).

27 Noise NOISE PRODUCED BY VIBRATION OR SHOCK WHILE DRIVING
No
Ye s Is speaker properly installed?
Noise is produced from static eletricity accumulating in the vehicle body. With vehicles stationary lightly tap each system.
Is noise produced?Install properly.
Each system faulty. Is speaker properly installed?
No
No Ye s
Ye s
28 Noise NOISE PRODUCED WHEN ENGINE STARTS
NoYe s Whistling noise which becomes high±pitched when
accelerator strongly depressed, disappears shortly
after engine stops.Generator noise.
A/C noise.
Fuel gauge noise.
Horn noise.
Ignition noise.
Turn signal noise.
Washer noise.
Engine coolant temp. gauge noise.
Wiper noise. Whining noise occurs when A/C is operating.
Scratching noise occurs during sudden acceleration, driving on rough
roads or when ignition switch is turned ON.
Clicking sound is heard when horn button is pressed, then
released. Whirring/grating sound is heard when pushed
continuously.
Murmuring sound stops when engine stops.
Tick±tack noise occurs in co±ordination with blinking
offlasher.
Noise occurs during window washer operation.
Scratching noise occurs while engine is running,
and continues a while even after engine stops.
Scraping noise in line with wiper beat.
Other type of noiseYe s
Ye s
Ye s
Ye s
Ye s
Ye s
Ye s
Ye s No
No
No
No
No
No
No
No
± BODY ELECTRICALAUDIO SYSTEM
BE±215
2516 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)

I04250

Combination Meter Wiring Circuit ± 1
:Speedometer
:Tachometer
:Fuel Receiver Gauge
:Engine Coolant
Temperature
Receiver Gauge
Speed Control Unit
CLOCK
to GAUGE Fuse
to MPX±B Fuse
to SRS Fuse
Tilt and Telescopic ECU
Body ECU NO.2ECM (GS400)
Ignitor (GS300)
Fuel Main Sender GaugeGround
Fuel Sub Sender Gauge
Light Control Rheostat
Illuminations
ABS, TRAC and VSC ECU
ABS, TRAC and VSC ECU Speed Signal Passenger seat
belt warning
Rr LIGHTS
SEAT BELT
OIL PRESS
OIL LEVEL
DOOR IG+
SRS +BA/T P
A/T R
A/T N
A/T D
A/T 4
A/T 3
A/T 2
A/T L
CRUISE MPX+BIG+IG+
5V
+B
to ECUto
PANEL
Fuse B4
B5
B6
B9
A5
A17A3A8 B16
LCDECU S
T
F
E
Power Source
Brake
Buzzer A11A2 A1 A6
B1
B13
B14A4
B22 ECU
ECU
ECU
S
T
F
E
CHARGE
FUEL LVL
ECT PWR
ECT SNOW TAIL or HEAD
Ground IG+IG+ IG+ IG+
+B
± BODY ELECTRICALCOMBINATION METER
BE±83
2384 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)

I04252
Engine
Coolant
Temperature
Receiver
Gauge
Tachometer
Speedometer
Fuel
Receiver
GaugeRight Turn Indicator Left Turn Indicator
ODO/TRIP Switch
RESET Switch TECOS+
TESIN+
TECOS± TESIN±
TACOS+
TASIN±
TASIN+
TACOS±
SPCOS±
SPSIN+
SPSIN±
SPCOS+
FUCOS±
FUSIN+TURN L
Power
Earth
TURN R
ODO/TRIP
RESET
HEAT±
Signal
Earth
Thermistor
SRS +B
C/C ±
C/C +
HEAT±
SRS +B Power
Earth O1
O2
O3
O4
P1
P2
P3
P4
Q1
Q2
Q3
Q4
R1
R2
R3G2 G1
G3
G4
G5
G6
G7
G8
L1
L2
L3
L4
L8
L12
K1
K3
K4
R4FUSIN±
FUCOS+C/C ±
C/C +K8
K12 Combination Meter ECU
Meter Circuit Plate ± 1
± BODY ELECTRICALCOMBINATION METER
BE±87
2388 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)