1996 TOYOTA LAND CRUISER air condition

AC2QC−03
−
AIR CONDITIONING AIR CONDITIONING SYSTEM
AC−3
1996 LAND CRUISER (RM451U)
PROBLEM SYMPTOMS TABLE
Use the table below to help you find the cause of the problem.The numbers i\
ndicate the priority of the likely
cause of the problem. Check each part in order. If necessary, replace these parts.
SymptomSuspect AreaSee page
No blower operation
4. HTR Fuse
5. Heater main relay
6. Blower motor
7. Blower resistor
8. Blower speed control switch
9. Wire harness−
AC−64
AC−52
AC−57
AC−69 −
No air temperature control
1. Engine coolant volume
2. A/C control assembly
3. Water valve−
AC−69
AC−49
No compressor operation
1. Refrigerant volume
2. A.C Fuse
3. Magnetic clutch
4. Compressor
5. Pressure switch
6. Heater main relay
7. Blower speed control switch
8. A/C switch
9. A/C amplifier
10.Thermistor
11. Wire harnessAC−5 −
AC−33
AC−33
AC−61
AC−64
AC−69
AC−69
AC−74
AC−60 −
Compressor operates intermitently
1. Refrigerant volume
2. Pressure switch
3. A/C amplifier
4. Thermistor
5. Wire harnessAC−5
AC−61
AC−74
AC−60 −
No cool air comes out
1. Refrigerant volume
2. Refrigerant pressure
3. Drive belt
4. Magnetic clutch
5. Compressor
6. Pressure switch
7. Thermistor
8. A/C switch
9. A/C amplifier
10.A/C control assembly
11. Wire harnessAC−5
AC−5
AC−15
AC−33
AC−33
AC−61
AC−60
AC−69
AC−74
AC−69 −
Cool air comes out only at high engine rpm
1. Refrigerant volume
2. Drive bel
3. Magnetic clutch
4. Compressor
5. Condenser
6. Receiver
7. Expansion valve
8. Evaporator
9. Thermistor
10.A/C amplifier
11. Wire harnessAC−5
AC−15
AC−33
AC−33
AC−42
AC−39
AC−47
AC−45
AC−60
AC−74 −
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AC−4
−
AIR CONDITIONING AIR CONDITIONING SYSTEM
1996 LAND CRUISER (RM451U)
Insuf
ficient cooling
1. Refrigerant volume
2. Drive belt
3. Magnetic clutch
4. Compressor
5. Condenser
6. Receiver
7. Expansion valve
8. Evaporator
9. Refrigerant line
10.Pressure switch
11. A/C amplifier
12.A/C control assemblyAC−5
AC−15
AC−33
AC−33
AC−42
AC−39
AC−47
AC−45
AC−20
AC−61
AC−74
AC−69
No engine idle up when A/C switch ON
1. A/C amplifier
2. ECM
3. Wire harnessAC−74 −
−
No warm air comes out
1. Engine coolant volume
2. A/C control assembly
3. Water valve
4. Heater radiator−
AC−69
AC−49
AC−46
A/C indicator does not light up when mode lever at DEF. position
1. Defroster mode switch
2. A/C switch
3. Wire harnessAC−69
AC−69 −
Rear heater:
SymptomSuspect AreaSee page
No blower operation
1. RR HTR Fuse
2. Rear heater relay
3. Rear heater switch
4. Rear blower motor
5. Rear blower resistor−
AC−65
AC−77
AC−55
AC−58
No warm air come out1. Engine coolant volume
2. Rear heater radiator−
AC−46
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N14063
AC2QD−01
I01386
−
AIR CONDITIONING AIR CONDITIONING SYSTEM
AC−5
1996 LAND CRUISER (RM451U)
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 set at ”HI”
A/C switch ON
Temperature control set at ”MAX. COOL”
Fully open doors
ItemSymptomAmount of refrigerantRemedy
1Bubbles present in sight glassInsufficient*
1. Check for gas leakage with gas leak
tester and repair if necessary
2. Add refrigerant until bubbles disappear
2No bubbles present in sight glassNone, sufficient or too muchRefer to items 3 and 4
3No temperature difference between compressor inlet and outletEmpty or nearly empty
1. Check for gas leakage with gas leaktester 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 turnedoff, 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,
refrigerant foams and then stays clearCorrect−
*: Bubbles in the sight glass with ambient temperatures higher
than usual can be considered normal if cooling is sufficient.
2. INSPECT REFRIGERAT PRESSURE WITH MANIFOLD
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 the
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 1,500 rpm
Blower speed control switch set at high
Temperature control set at max. cool
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)
SightGlass
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I01387
Condition : Periodically cools and then fails to cool
I01388
Condition: Insufficient cooling
AC−6
−
AIR CONDITIONING AIR CONDITIONING SYSTEM
1996 LAND CRUISER (RM451U)
(2) Moisture present in refrigeration system.
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
During operation, pressure on low
pressure side sometimes become
a vacuum and sometime normal
Moisture entered in refrigeration
system freezes at expansion valve
orifice and temporarily stops cycle,
but normal state is restored after a
time when the ice melts Drier in oversaturated state
 Moisture in refrigeration system
freezes at expansion valve orifice
and blocks circulation of refriger-
ant(1) Replace condenser
(2) Remove moisture in cycle
through repeatedly evacuating air
(3) Charge proper amount of new
refrigerant
(3) Insufficient cooling
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Pressure low on both low and
high pressure sides
 Bubbles seen in sight glass con-
tinuously
 Insufficient cooling performance
Gas leakage at some place in re-
frigeration system Insufficient refrigerant in system
 Refrigerant leaking
(1) Check for gas leakage with gas
leak detector and repair if neces-
sary
(2) Charge proper amount of re-
frigerant
(3) If indicated pressure value is
near 0 when connected to gauge,
create the vacuum after inspecting
and repairing the location of the
leak
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I01389
Condition: Insufficient cooling
I01449
Condition: Does not cool (Cools from time to time in some cases)
−
AIR CONDITIONING AIR CONDITIONING SYSTEM
AC−7
1996 LAND CRUISER (RM451U)
(4) Poor circulation of refrigerant
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Pressure low in both low and
high pressure sides
 Frost on tube from condenser to
unit
Refrigerant flow obstructed by dirt
in condensercondenser cloggedReplace condenser
(5) Refrigerant does not circulate
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Vacuum indicated on low pres-
sure side, very low pressure indi-
cated on high pressure side
 Frost or dew seen on piping be-
fore and after condenser/ drier or
expansion valve Refrigerant flow obstructed by
moisture or dirt in refrigeration sys-
tem
 Refrigerant flow obstructed by
gas leakage from expansion valve
Refrigerant does not circulate
(1) Check expansion valve
(2) Clean out dirt in expansion
valve by blowing with air
(3) Replace condenser
(4) Evacuate air and charge new
refrigerant to proper amount
(5) For gas leakage from expan-
sion valve, replace expansion
valve
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I01390
Condition: Insufficient cooling
I01392
Condition: Insufficient coolingNOTE : These gauge indica-
tions are shown when the
refrigeration system has
been opened and the refrig-
erant charged without vacu-
um purging.
AC−8
−
AIR CONDITIONING AIR CONDITIONING SYSTEM
1996 LAND CRUISER (RM451U)
(6) Refrigerant overcharged or insufficient cooling of
condenser
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Pressure too high on both low
and high pressure sides
 No air bubbles seen through the
sight glass even when the engine
rpm is lowered Unable to develop sufficient per-
formance due to excessive refrig-
eration system
 Insufficient cooling of condenser Excessive refrigerant in
cycle → refrigerant over charged
 Condenser cooling → condenser
fins clogged or cooling fan faulty
(1) Clean condenser
(2) Check cooling fan with fluid
coupling operation
(3) If (1) and (2) are in normal
state, check amount of refrigerant
Charge proper amount of refriger-
ant
(7) Air present in refrigeration system
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Pressure too high on both low
and high pressure sides
 The low pressure piping hot to
touch
 Bubbles seen in sight glass
Air entered in refrigeration system
 Air present in refrigeration sys-
tem
 Insufficient vacuum purging
(1) Check compressor oil to see if
it is dirty or insuf ficient
(2) Evacuate air and charge new
refrigerant
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I01450
Condition: Insufficient cooling
I01393
Condition : Does not cool
−
AIR CONDITIONING AIR CONDITIONING SYSTEM
AC−9
1996 LAND CRUISER (RM451U)
(8) Expansion valve improperly
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Pressure too high on both low
and high pressure sides
 Frost or large amount of dew on
piping on low pressure side
Trouble in expansion valve
 Excessive refrigerant in low
pressure piping
 Expansion valve opened too
wide
Check expansion valve
Replace if defective
(9) Defective compression compressor
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
 Pressure too high on low and
high pressure sides
 Pressure too low on high pres-
sure side
Internal leak in compressor
 Compression defective
 Valve leaking or broken sliding
parts
Repair or replace compressor
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AC−10
−
AIR CONDITIONING AIR CONDITIONING SYSTEM
1996 LAND CRUISER (RM451U)
3. INSPECT IDLE−UP SPEED
(a) Warm up engine
(b) Inspect idle −up speed when the these conditions are es-
tablished:
Blower switch HI
Electrical load OFF
A/C switch ON
Put gear shift in neutral
Magnetic clutch conditionIdle speed
Magnetic clutch not engaged650 ± 50 rpm
Magnetic clutch engaged800 ± 50 rpm
If idle speed is not as specified, check the IAC valve and air in-
take system.
4. INSPECT FOR LEAKAGE OF REFRIGERANT
(a) Perform in these conditions:
Stop engine.
Secure good ventilation (If not, the gas leak detec-
tor may react to volatile gases which are not refrig-
erant, such as evaporated gasoline and exhaust
gas.)
Repeat the test 2 or 3 times.
Make sure that there is some refrigerant remaining
in the refrigeration system.
When compressor is OFF: approximately 392 − 588
KPa (4 − 6 kgf/cm
2, 57 − 35 psi)
(b) Bring the gas leak detector close to the drain hose before
performing the test.
HINT:
After the blower motor is stopped, leave the cooling unit
for more than 15 minutes.
Expose the gas leak detector sensor the under the drain
hose.
When bring the gas leak detector close to the drain hose,
make sure that the gas leak detector does not react to the
volatile gases.
If such reaction is unavoidable, the vehicle must be lifted up.
(c) If gas leak is not detected on the drain hose, remove the
power transistor from the cooling unit. Then insert the gas
leak detector sensor into the unit and perform the test.
(d) Disconnect the connector and leave the pressure switch for approximately 20 minutes. Then bring the gas leak de-
tector close to the pressure switch and perform the test.
(e) Bring the gas leak detector close to the refrigerant lines and perform the test.
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