fold LEXUS GS400 2000 Service Repair Manual

AC2810
AC0W6±01
AC2811
N11084
Wrong Okay
HI LO HILO
± AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC±1
2686 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
AIR CONDITIONING SYSTEM
PRECAUTION
1. DO NOT HANDLE REFRIGERANT IN AN ENCLOSED
AREA OR NEAR AN OPEN FLAME
2. ALWAYS WEAR EYE PROTECTION
3. BE CAREFUL NOT TO GET LIQUID REFRIGERANT IN
YOUR EYES OR ON YOUR SKIN
If liquid refrigerant gets in your eyes or on your skin.
(a) Wash the area with lots of cool water.
CAUTION:
Do not rub your eyes or skin.
(b) Apply clean petroleum jelly to the skin.
(c) Go immediately to a physician or hospital for professional
treatment.
4. NEVER HEAT CONTAINER OR EXPOSE IT TO NAKED
FLAME
5. BE CAREFUL NOT TO DROP CONTAINER AND NOT
TO APPLY PHYSICAL SHOCKS TO IT
6. DO NOT OPERATE COMPRESSOR WITHOUT
ENOUGH REFRIGERANT IN REFRIGERANT SYSTEM
If there is not enough refrigerant in the refrigerant system oil lu-
brication will be insufficient and compressor burnout may occur,
so take care to avoid this, necessary care should be taken.
7. DO NOT OPEN HIGH PRESSURE MANIFOLD VALVE
WHILE COMPRESSOR IS OPERATING
If the high pressure valves opened, refrigerant flows in the re-
verse direction and could cause the charging cylinder to rup-
ture, so open and close the only low pressure valve.
8. BE CAREFUL NOT TO OVERCHARGE SYSTEM WITH
REFRIGERANT
If refrigerant is overcharged, it causes problems such as insuffi-
cient cooling, poor fuel economy, engine overheating etc.

AC0W8±01
N13795
Quick Disconnect
Adapter
Charging
Service ValveHose
N13794
Vacuum Pump
Vacuum Pump Adapter
N13791
Low Pressure
Service Valve
Vacuum Pump Adapter High Pressure
Service ValveManifold
Gauge
Set
AC±10
± AIR CONDITIONINGAIR CONDITIONING SYSTEM
2695 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
EVACUATING
1. CONNECT QUICK DISCONNECT ADAPTER TO
CHARGING HOSES
2. REMOVE CAPS FROM SERVICE VALVES ON RE-
FRIGERANT LINES
3. SET ON MANIFOLD GAUGE SET
(a) Close both hand valves of manifold gauge set.
(b) Connect the quick disconnect adapters to the service
valves.
4. EVACUATE AIR FROM REFRIGERATION SYSTEM
(a) Connect the vacuum pump adapter to the vacuum pump.
(b) Connect the center hose of the manifold gauge set to the
vacuum pump adapter.
(c) Open both the high and low hand valves and run the vacu-
um pump.
(d) After 10 minutes or more, check that the low pressure
gauge indicates 750 mmHg (30 in. Hg) or more.
HINT:
If the reading is 750 mmHg (30 in. Hg) or more, close both hand
valves of manifold gauge set and stop the vacuum pump.
Check the system for leaks and repair if necessary.
(e) Close both the high and low hand valves and stop the vac-
uum pump.
(f) Leave the system in this condition for 5 minutes or more
and check that there is no gauge indicator.

AC0W9±01
N13793
Charging Cylinder High Pressure
Service Valve Low Pressure
Service ValvePush
Air
N13792
Gas Leak
Detector
± AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC±11
2696 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
CHARGING
1. INSTALL CHARGING CYLINDER
HINT:
When handling the charging cylinder, always follow the direc-
tions given in the instruction manual.
(a) Charge the proper amount of refrigerant into the charging
cylinder.
(b) Connect the center hose to the charging cylinder.
CAUTION:
Do not open both high and low hand valves of manifold
gauge set.
(c) Open the valve of charging cylinder.
(d) Press the valve core on the side of manifold gauge and
expel the air inside of the center hose.
2. INSPECT REFRIGERATION SYSTEM FOR LEAKS
(a) Open the high pressure hand valve and charge refriger-
ant.
(b) When the low pressure gauge indicates 98 kPa
(1 kgf/cm
2, 14 psi) close the high pressure hand valve.
(c) Using a gas leak detector, check the system for leakage.
If leak is found, repair the faulty component or connection.
CAUTION:
Use the refrigerant recovery/ recycling machine to recover
the refrigerant whenever replacing parts.

N13790
Low Pressure
Service Valve
High Pressure
Service Valve
AC±12
± AIR CONDITIONINGAIR CONDITIONING SYSTEM
2697 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
3. INSTALL CHARGING CYLINDER
HINT:
When handling the charging cylinder, always follow the direc-
tions given in the instruction manual.
(a) Charge the proper amount of refrigerant into the charging
cylinder.
(b) Connect the center hose to the charging cylinder.
CAUTION:
Do not open both high and low hand valves of manifold
gauge set.
(c) Open the valve of charging cylinder.
(d) Press the valve core on the side of manifold gauge and
expel the air inside of the center hose.
A fully charged system is indicated by the sight glass being free
of any bubbles.
4. SET OFF MANIFOLD GAUGE SET
(a) Close both hand valves of manifold gauge set.
(b) Disconnect the quick disconnect adapters from the ser-
vice valves.
5. INSTALL CAPS TO SERVICE VALVES ON REFRIGER-
ANT LINES

I02353
GS400:
Low Pressure
Charging HoseHigh Pressure
Charging Hose
I02354
GS300:
Low Pressure
Charging HoseHigh Pressure
Charging HoseAC0WE±01
N04392
Sleeve
± AIR CONDITIONINGMANIFOLD GAUGE SET
AC±17
2702 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
MANIFOLD GAUGE SET
SET ON
1. CONNECT CHARGING HOSES TO MANIFOLD
GAUGE SET
Tighten the nuts by hand.
CAUTION:
Do not connect the wrong hoses.
2. CONNECT QUICK DISCONNECT ADAPTERS TO
CHARGING HOSES
Tighten the nuts by hand.
3. CLOSE BOTH HAND VALVES OF MANIFOLD GAUGE
SET
4. REMOVE CAPS FROM SERVICE VALVE ON REFRIG-
ERANT LINES
5. CONNECT QUICK DISCONNECT ADAPTERS TO SER-
VICE VALVES
HINT:
Push the quick disconnect adapter onto the service valve, then
slide the sleeve of the quick disconnect adapter downward to
lock it.

AC0WF±01
N06553
AC±18
± AIR CONDITIONINGMANIFOLD GAUGE SET
2703 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
SET OFF
1. CLOSE BOTH HAND VALVES OF MANIFOLD GAUGE
SET
2. DISCONNECT QUICK DISCONNECT ADAPTERS
FROM SERVICE VALVES ON REFRIGERANT LINE
HINT:
Slide the sleeve of the quick disconnect adapter upward to un-
lock the adapter and remove it from the service valve.
3. INSTALL CAPS TO SERVICE VALVES ON REFRIGER-
ANT LINES

I01386
AC±4
± AIR CONDITIONINGAIR CONDITIONING SYSTEM
2689 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
2. INSPECT REFRIGERANT PRESSURE WITH MAN-
IFOLD GAUGE SET
This is a method in which the trouble is located by using a man-
ifold gauge set. Read the manifold gauge pressure when these
conditions are established.
Test conditions:

Temperature at the air inlet with the switch set
at RECIRC is 30 ± 35 °C (86 ± 95 °F)

Engine running at 2,000 rpm

Blower speed control switch at ºHIº position

Temperature control dial on ºCOOLº position
HINT:
It should be noted that the gauge indications may vary slightly
due to ambient temperature conditions.
(1) Normally functioning refrigeration system.
Gauge reading:
Low pressure side:
0.15 ± 0.25 MPa (1.5 ± 2.5 kgf/cm
2)
High pressure side:
1.37 ± 1.57 MPa (14 ± 15 kgf/cm
2)

AC0X8±01
AC±58
± AIR CONDITIONINGEXPANSION VALVE
2743 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
EXPANSION VALVE
ON±VEHICLE INSPECTION
1. CHECK QUANTITY OF GAS DURING REFRIGERATION CYCLE
2. SET ON MANIFOLD GAUGE SET
(See page AC±17)
3. RUN ENGINE
Run the engine at 1,500 rpm for at least 5 minutes.
Then check that the high pressure reading is 1.37 ± 1.57 MPa (14 ± 16 kgf/cm
2, 199 ±228 psi).
4. CHECK EXPANSION VALVE
If the expansion valve is faulty, the low pressure reading will drop to 0 kPa (0 kgf/cm
2, 0 psi).

I03741
2 1
3
4
AC0XN±01
Z13470
Magnetic Clutch Control
Low Pressure Side
ON (Continuity)
181 kpa
(1.85 kgf´cm
2, 28 psi)
OFF (No Continuity)High Pressure Side
3,140 kpa
(32.0 kgf´cm2, 455 psi)
OFF (No Continuity)
Z13471
Cooling Fan Control
ON1,520 kpa
(15.5 kgf´cm
2, 220 psi)
(No Continuity) (Continuity)
OFF
1,230 kpa
(12.5 kgf´cm
2, 178 psi) AC±76
± AIR CONDITIONINGPRESSURE SWITCH
2761 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
PRESSURE SWITCH
ON±VEHICLE INSPECTION
1. SET ON MANIFOLD GAUGE SET
(See page AC±17)
2. DISCONNECT CONNECTOR FROM PRESSURE
SWITCH
3. RUN ENGINE AT APPROX. 1,500 RPM
4. Magnetic Clutch Control:
INSPECT PRESSURE SWITCH OPERATION
(a) Connect the positive (+) lead from the ohmmeter to termi-
nal 4 and the negative (±) lead to terminal 1.
(b) Check continuity between terminals when refrigerant
pressure is changed, as shown in the illustration.
If operation is not as specified, replace the pressure switch.
5. Cooling Fan Control:
INSPECT PRESSURE SWITCH OPERATION
(a) Connect the positive (+) lead from the ohmmeter to termi-
nal 2 and the negative (±) lead to terminal 3.
(b) Check continuity between terminals when refrigerant
pressure is changed, as shown in the illustration.
If operation is not as specified, replace the pressure switch.
6. STOP ENGINE AND SET OFF MANIFOLD GAUGE SET
7. CONNECT CONNECTOR TO PRESSURE SWITCH

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.