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.

AC±2
± AIR CONDITIONINGAIR CONDITIONING SYSTEM
2687 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
9. SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
The Lexus GS 300/ 400 is equipped with an SRS (Supplemen-
tal Restraint System) such as the driver and passenger airbag.
Failure to carry out service operations in the correct sequence
could cause the SRS to unexpectedly deployed during servic-
ing, possibly leading to a serious accident. Further, if a mistake
is made in servicing the SRS, it is possible the SRS may fail to
operate when required. Before servicing ( including removal or
installation of parts, inspection or replacement), be sure to read
the following item carefully, then follow the correct procedure
described in repair manual.

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

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

CH0086
Correct Wrong
AC0WB±01
I03853
GS 400:A
B
P10652
GS 300:
Type A
Type BAB
AB AC±14
± AIR CONDITIONINGDRIVE BELT
2699 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
DRIVE BELT
ON±VEHICLE INSPECTION
1. INSPECT DRIVE BELT'S INSTALLATION CONDITION
Check that the drive belt fits properly in the ribbed grooves.
2. INSPECT DRIVE BELT TENSION
Check that the arrow mark on the belt tensioner falls within area
ºAº of the scale.
If it is out side area ºAº, replace the drive belt.
HINT:
When a new belt is installed, it should be lie within area B.

AC0WC±01
I03854
GS300:
Turn
I03855
GS400:
± AIR CONDITIONINGDRIVE BELT
AC±15
2700 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
REMOVAL
1. GS 300:
REMOVE DRIVE BELT
Loosen the drive belt tension by turning the drive belt tensioner
clockwise and remove the drive belt.
2. GS 400:
REMOVE DRIVE BELT
Loosen the drive belt tension by turning the drive belt tensioner
counterclockwise and remove the drive belt.

AC0WD±01
AC±16
± AIR CONDITIONINGDRIVE BELT
2701 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSTALLATION
Installation is in the reverse order of removal (See page AC±15).
AFTER INSTALLATION, CHECK DRIVE BELT'S INSTALLATION CONDITION

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.