2000 LEXUS GS400 Service Repair Manual

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.

I02362
I02363
± AIR CONDITIONINGAIR CONDITIONING UNIT
AC±25
2710 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
5. REMOVE THESE PARTS:
(a) Cooler No.1 grommet
(b) Heater pipe grommet
(c) Drain hose grommet
(d) Instrument panel and reinforcement
(See page BO±91)
(e) Blower unit
(See page AC±30)
6. REMOVE 3 AIR DUCTS
(a) Remove the 2 screws and center air duct.
(b) Slide the floor carpet backward.
(c) Disconnect the wire harness clamps.
(d) Remove the 2 bolts and air ducts LH, RH.
7. REMOVE A/C UNIT
(a) Disconnect the connector.
(b) Remove the wire harness set nut.
(c) Disconnect the wire harness clamps.
(d) Remove the 2 nuts, bolt and A/C unit.

AC0WL±01
AC±26
± AIR CONDITIONINGAIR CONDITIONING UNIT
2711 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
DISASSEMBLY
1. REMOVE THESE PARTS:
(a) Wire harness
(b) Drain hose
2. REMOVE HEATER RADIATOR
(a) Remove the screw and clamp.
(b) Pull out the heater radiator.
3. REMOVE BLOWER MOTOR CONTROL RELAY
Remove the screw and blower motor control relay.
4. REMOVE AIR MIX SERVOMOTORS
Remove the 6 screws and both servomotors.
5. REMOVE AIR OUTLET SERVOMOTOR
Remove the 2 screws and servomotor.
6. REMOVE EXPANSION VALVE
(a) Pry out the packing.
HINT:
At the time of reassembly, please refer to the following item.
Do not reuse the packing.
(b) Using SST, remove the 2 bolts, then separate the expansion valve, tube connector and tube and ac-
cessory.
SST 07110±61050
Torque: 4.1N´m (42 kgf´cm, 36 in.´lbf)
HINT:
At the time of reassembly, please refer to the following item.
Lubricate 4 new O±rings with compressor oil and install them to the valve.
7. REMOVE EVAPORATOR TEMPERATURE SENSOR
(a) Disconnect the wire harness clamp.
(b) Using a screwdriver, pull out the sensor with bracket plate.
HINT:
Tape the screwdriver tip before use.
(c) Release the 2 claws and sensor from bracket plate.
8. REMOVE EVAPORATOR
(a) Using SST, remove the 2 bolts and tube and accessory.
SST 07110±61050
Torque: 4.1N´m (42 kgf´cm, 36 in.´lbf)
HINT:
At the time of reassembly, please refer to the following item.
Lubricate 2 new O±rings with compressor oil and install them to the tube.
(b) Remove the 4 screws and cover.
(c) Pull out the evaporator.
(d) Remove the plate from evaporator.
HINT:
At the time of reassembly, please refer to the following item.
If evaporator is replaced, add compressor oil to evaporator.
Add 40 cc (1.4fl.oz.)
Compressor oil: ND±OIL 8 or equivalent
9. REMOVE INSULATOR FROM HEATER CASE
10. REMOVE AIR DUCT
Remove the 4 screws and duct.

AC0WM±01
± AIR CONDITIONINGAIR CONDITIONING UNIT
AC±27
2712 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
REASSEMBLY
Reassembly is in the reverse order of disassembly (See page AC±26).

AC0WN±01
AC±28
± AIR CONDITIONINGAIR CONDITIONING UNIT
2713 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSTALLATION
Installation is in the reverse order of removal (See page AC±24).

AC0WO±01
I02372 I02370
I02371
Instrument Panel
Reinforcement
Blower Unit
Bracket
Wire Harness
Air Duct
No.2 Brace
No.1 Brace
Air Refiner Filter
Cover
Blower Motor Air Inlet Servomotor
Blower Unit Case
± AIR CONDITIONINGBLOWER UNIT
AC±29
2714 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
BLOWER UNIT
COMPONENTS

AC0W7±02
I02352
Sight Glass
± AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC±3
2688 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
ON±VEHICLE INSPECTION
1. INSPECT REFRIGERANT VOLUME
Observe the sight glass on the liquid tube.
Test conditions:

Running engine at 1,500 rpm

Blower speed control switch at ºHIº position

A/C switch ON

Temperature control dial at ºCOOLº position

Fully open the doors
ItemSymptomAmount of refrigerantRemedy
1Bubbles present in sight glassInsufficient*
(1) Check for gas leakage with gas leak de-
tector and repair if necessary
(2) Add refrigerant until bubbles disappear
2No bubbles present in sight glassNone, sufficient or too muchRefer item 3 and 4
3No temperature difference between com-
pressor inlet and outletEmpty or nearly empty
(1) Check for gas leakage with gas leak de-
tector and repair if necessary
(2) Add refrigerant until bubbles disappear
4Temperature between compressor inlet and
outlet is noticeably differentCorrect or too muchRefer to items 5 and 6
5Immediately after air conditioning is turned
off, refrigerant in sight glass stays clearToo much
(1) Discharge refrigerant
(2) Evacuate air and charge proper amount
of purified refrigerant
6When air conditioning is turned off, refriger-
ant foams and then stays clearCorrect±
*: Bubbles in the sight glass with ambient temperatures higher than usual can be considered normal if cooling
is sufficient.

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)