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HVAC
Air Conditioning System
Manual Type
Precautions
A/C System CautionS7RS0B7210001
CAUTION!
• The air conditioning system of this vehicle uses refrigerant HFC-134a (R-134a).
None of refrigerant, compressor oil and component parts is interchangeable between two types of
A/C: one using refrigerant HFC-134a (R-134a) and the other using refrigerant CFC-12 (R-12).
Be sure to check which refrigerant is used be fore any service work including inspection and
maintenance. For identification between these two types, refer to “Refrigerant Type Identification”.
When replenishing or changing refrigerant and comp ressor oil and when replacing parts, make sure
that the material or the part to be used is appropriate to the A/C installed in the vehicle being
serviced.
Use of incorrect one will result in leakage of refrigerant, damage in parts or other faulty condition.
• When servicing the compressor, keep dirt or foreign material away from getting on or into the compressor parts and system. Clean tools and a clean work area are important for proper service.
The compressor connection and the outside of the compressor should be cleaned before any “On
vehicle” repair or before removal of the compressor. The parts must be kept clean at all times and
any parts to be reassembled should be cleaned with trichloromethane, naphtha, kerosene or
equivalent solvent and dried with dry air. Use only lint free cloths to wipe parts.
• When compressor is removed from the vehicle for servicing, the oil remaining in the compressor
should be discarded and new refrigerant oil added to the compressor.
Minor repair procedures may be done on the vehicle without discharging the system. Major repair
procedures require that the system be discharged of refrigerant.
Precautions on Servicing A/C SystemS7RS0B7210002
WARNING!
Should refrigerant HFC-134a (R-134a) is exposed to your eye(s), consult a doctor immediately.
• Do not use your hand to rub affected eye(s). Instead, use fresh cold water to splash it over affected area to thus gradually raise its temperature above the freezing point.
• Obtain proper treatment as soon as possible from a doctor or eye specialist. Should liquid refrigerant HFC-134a (R-134a) is exposed to your skin, such affected part should be treated in the
same manner as when skin is frostbitten or frozen.
Handling Refrigerant HFC-134a (R-134a)
• Always wear goggles to protect your eyes.
• Avoid direct contact to liquid refrigerant.
• Do not heat refrigerant container higher than 40 °C (104 ° F).
• Do not discharge refrigerant into atmosphere.
• Do not expose bright metals to liquid refrigerant. Refrig erant combined with moisture is corrosive and tarnishes
surfaces of bright metals including chrome.
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Schematic and Routing Diagram
Major Components of A/C SystemS7RS0B7212001
Airflow diagram
Major components of A/C system
I4RS0A720003-01
7
2
34
1 8
6
5
I4RS0B720002-01
1. HVAC unit 5. Discharge hose9. Side ventilation air 13. Side defroster air
2. Compressor 6. Suction hose10. Center ventilation air 14. Fresh air
3. Condenser assembly 7. Liquid pipe11. Foot air 15. Recirculation air
4. Receiver/dryer (Modulator) 8. Expansion valve12. Front defroster air 16. Evaporator
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A/C System Wiring DiagramS7RS0B7212002
BLK/REDBLK/RED
BLK/YELBLK/YEL
BLK/YEL
BRN/WHT
12V5V
5V 5V
5V11
E23-1
E23-60
BLK/REDBLK/REDE23-16
E23-57WHT/BLK
9
13
E23-55C37-14GRY/REDRED
BLK
ORN
E23-47 GRY
WHTBLU/YEL
RED/BLK
14 3
1
15
5
7
BLK
2
M
12VBLU/WHTE23-19
C37-24
C37-55ORN
5V
LT GRN16
G18-3
G18-4
G18-7
G18-8
G18-10
G18-13
G18-5
G18-6
G19-5
G19-2
G19-3
G19-7
G19-6
G19-1
G18-9
G18-14
BLK/WHT
YEL
BLU/WHT
RED
BRN/WHT
GRN/WHT
RED/BLK
RED
GRN
BRN
BLK/RED
RED/YEL
BLK
BLK/YEL
BLK/ORN
4
6
12
10
M
E23-54
REDWHTE23-3E23-18
17 18
LT GRNE23-46
L+
L–
H–
H
+
BLU/RED
BLK
BLU/WHTBLK
BLU/BLK
20
GRN
GRY
E23-48
19
21
22
BLU/REDC37-58
C37-15 C37-30
BLK/ORN
BLKBLKE23-31 BLK
BLU
YEL
GRN
WHT
23
24
26 25
28
27
8
29
I7RS0B721001-01
1. Ignition switch
9. A/C refrigerant pressure sensor 17. I ndividual circuit fuse box (No.1) 25. Air intake selector
2. Blower motor 10. ECM 18. Main fuse box 26. Rear defogger switch
3. HVAC control unit 11. Main relay 19. Radiator cooling fan relay No.1 27. Rear defogger
4. Lighting switch 12. Air intake control actuator 20. Radiator cooling fan relay No.2 28. Rear defogger relay
5. Blower motor relay 13. Compressor relay 21. Radiator cooling fan relay No.3 29. ABS / ESP ® control module
6. Blower motor resistor 14. Compressor 22. Radiator cooling fan motor
7. Junction block assembly 15. Evaporator thermistor (evaporator temperature sensor)23. Blower speed selector
8. BCM 16. ECT sensor 24. A/C switch
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Cool air does not come
out or insufficient cooling
(A/C system normal
operation)Insufficient or excessive charge of
refrigerant
Check the amount of refrigerant and system
for leaks.
Condenser clogged Check condenser referring to “Condenser
Assembly On-Vehicle Inspection”.
A/C evaporator clogged or frosted Check A/C evaporator and evaporator
thermistor (evaporator temperature sensor)
referring to “Evaporator Inspection” and
“Evaporator Thermistor (Evaporator
Temperature Sensor) Inspection”.
Evaporator thermistor (Evaporator
temperature sensor) faulty Check evaporator thermistor (Evaporator
temperature sensor) referring to “Evaporator
Thermistor (Evaporator Temperature Sensor)
Inspection”.
Expansion valve faulty Check expansion valve referring to “Expansion
Valve Inspection”.
Desiccant clogged Replace receiver/dryer.
Compressor drive belt loosened or
broken Adjust or replace drive belt.
Magnet clutch faulty Check magnet clutch referring to “Magnet
Clutch Inspection”.
Compressor faulty Check compressor.
Air in A/C system Replace receiver/dryer, and then perform
evacuation and charge referring to “Operation
Procedure for Refrigerant Charge”.
Air leaking from HVAC unit or air duct Repair as necessary.
Heater and ventilation system faulty Check HVAC unit.
Blower motor faulty Check blower motor referring to “Blower Motor
Inspection in Section 7A”.
Excessive compressor oil in A/C system Drain excessive compressor oil from A/C
system circuit and compressor.
Cool air does not come
out only intermittently Wiring connection faulty
Repair as necessary.
Expansion valve faulty Check expansion valve referring to “Expansion
Valve Inspection”.
Excessive moisture in A/C system Replace receiver/dryer, and then perform
evacuation and charge referring to “Operation
Procedure for Refrigerant Charge”.
Magnet clutch faulty Check magnet clutch referring to “Magnet
Clutch Inspection”.
Excessive amount of refrigerant Check the amount of refrigerant.
Cool air comes out only
when driving vehicle at
high speed Condenser clogged
Check condenser referring to “Condenser
Assembly On-Vehicle Inspection”.
Insufficient charge of refrigerant Check the amount of refrigerant and system
for leaks.
Air in A/C system Replace receiver/dryer, and then perform
evacuation and charge referring to “Operation
Procedure for Refrigerant Charge”.
Compressor drive belt loosened or
broken Adjust or replace drive belt.
Compressor faulty Check compressor.
Cool air does not come
out only when driving
vehicle at high speed Excessive amount of refrigerant
Check the amount of refrigerant.
A/C evaporator frosted Check A/C evaporator and evaporator
thermistor (evaporator temperature sensor)
referring to “Evaporator Inspection” and
“Evaporator Thermistor (Evaporator
Temperature Sensor) Inspection”.
Condition Possible cause Correction / Reference Item
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Abnormal Noise Symptom Diagnosis of A/C SystemS7RS0B7214002
Abnormal Noise from Compressor
Abnormal Noise from Magnetic Clutch
Abnormal Noise from Tubing
Abnormal Noise from Condenser Assembly
Abnormal Noise from Crankshaft PulleyInsufficient airflow of
cooled air
A/C evaporator clogged or frosted
Check A/C evaporator and evaporator
thermistor (evaporator temperature sensor)
referring to “Evaporator Inspection” and
“Evaporator Thermistor (Evaporator
Temperature Sensor) Inspection”.
Air leaking from HVAC unit or air duct Repair as necessary.
Blower motor faulty Check blower motor referring to “Blower Motor
Inspection in Section 7A”.
Wiring or grounding faulty Repair as necessary.
Condition Possible cause Correction / Reference Item
Condition
Possible cause Correction / Reference Item
During compressor
operation, a rumbling
noise is heard
proportional to engine
revolutions Inadequate clearance in scroll area
Replace compressor.
A loud noise is heard at a
certain rpm,
disproportionately to
engine revolution Loose or faulty compressor drive belt
Adjust drive belt tension or replace drive belt.
Loose compressor mounting bolts Retighten mounting bolts.
A loud rattle is heard at
low engine rpm Loose compressor clutch plate bolt
Retighten clutch plate bolt.
Replace compressor if it was operated in this
condition for a long time.
Condition Possible cause Correction / Reference Item
A rumbling noise is heard
when compressor is not
in operation Worn or damaged bearings
Replace magnet clutch assembly.
A chattering noise is
heard when compressor
is in operation Faulty magnet clutch clearance
(excessive clearance)
Adjust magnet clutch clearance.
Worn magnet clutch friction surface Replace magnet clutch assembly.
Compressor oil leaked from shaft seal,
contaminating the friction surface Replace compressor body assembly.
Condition
Possible cause Correction / Reference Item
A droning noise is heard
from inside of the vehicle,
but not particularly
noticeable in engine
compartment Faulty tubing clamps
Reposition clamps or increase the number of
clamps.
Resonance caused by pulsation from
variations in re frigerant pressure Attach a silencer to tubing, or modify its
position and length.
Condition
Possible cause Correction / Reference Item
Considerable vibration in
condenser assembly Resonance from condenser assembly
bracket and body Firmly insert a silenc
er between condenser
assembly bracket and body.
Condition Possible cause Correction / Reference Item
A large rattling noise is
heard at idle or sudden
acceleration Loosen crankshaft pulley bolt
Retighten bolt.
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Abnormal Noise from Tension Pulley
Abnormal Noise from A/C Evaporator
Abnormal Noise from Blower Motor
A/C System Performance InspectionS7RS0B7214003
1) Confirm that vehicle and environmental conditions are as follows.
• Vehicle is put indoors.
• Ambient temperature is within 25 – 35 °C (77 – 95
° F).
• Relative humidity is within 30 – 70%.
• There is no wind indoors.
• HVAC unit is normal.
• Blower motor is normal.
• There is no air leakage from air ducts.
• Condenser fins are clean.
• Air filter in HVAC unit is not clogged with dirt and
dust.
• Battery voltage is about 12 V.
• Radiator cooling fan operates normally.
2) Make sure that high pressure valve (1) and low pressure valve (2) of manifold gauge are firmly
closed.
3) Connect high pressure charging hose (3) to high pressure service valve (5) on vehicle and low
pressure charging hose (4) to low pressure service
valve (6).
4) Bleed the air in charging hoses (3) and (4) by loosening their nuts respectively utilizing the
refrigerant pressure. When a hissing sound is heard,
immediately tighten nut.
CAUTION!
Do not connect high and low pressure
charging hoses in reverse.
Condition Possible cause Correction / Reference Item
Clattering noise is heard
from pulley Worn or damaged bearing
Replace tension pulley.
Pulley cranks upon
contact Cracked or loose bracket
Replace or retighten bracket.
ConditionPossible cause Correction / Reference Item
Whistling sound is heard
from A/C evaporator Depending on the combination of the
interior / exterior temperatures, engine
rpm and refrigerant pressure, the
refrigerant flowing out of the expansion
valve may, under certain conditions,
make a whistling sound At times, slightly decrea
sing refrigerant volume
may stop this noise.
Inspect expansion valve and replace if faulty.
Condition Possible cause Correction / Reference Item
Blower motor emits a
chirping sound in
proportion to its speed of
rotation Worn or damaged motor brushes or
commutator
Replace blower motor.
Fluttering noise or large
droning noise is heard
from blower motor Leaves or other debris introduced from
fresh air inlet to blower motor
Remove debris and make sure that the screen
at fresh air inlet is intact.
53
2
1
4 6
I4RS0A720006-01
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5) Warm up engine to the normal operating temperature and keep it at the specified idle speed.
6) Turn A/C switch ON, set blower speed selector at maximum speed position, temperature selector at
maximum cold position, airflow selector at face
position, and air intake switch at recirculation
position. (Confirm that A/C compressor and
condenser fans are working.)
7) Wait for ten minutes to stabilize the A/C operation.
8) Open front windows, front doors and engine hood.
9) With about 20 mm (0.8 in.) of dry bulb thermometer
(1) put right in front of center ventilation louver and a
wet and dry bulb thermometer (2) near air inlet of
HVAC unit. 10) Check for each pressure of low side and high side if
it is within shaded range of graph. If each gauge
reading is out of specified pressure, correct defective
part referring to the following table.
NOTE
Pressure registered on gauge varies with
ambient temperature. Therefore, use the
graphs when determining if pressures are
normal or not.
Low side and high side pressure example,
Gauges should read as follows when ambient
temperature is 30 °C (86 °F)
Pressure on high pressure gauge (HI): 1590 –
1940 kPa (15.9 – 19.4 kg/cm2)
Pressure on low pressure gauge (LO): 270 – 430
kPa (2.7 – 4.3 kg/cm
2)
2
1
I4RS0B720004-01
[A]: Pressure of high pressure gauge
[B]: Pressure of low pressure gauge
[C]: Ambient temperature
[D]: Humidity [E]: Acceptable range
22
312.9 2200
0 1
2 3 30 70 30 70 %
4 5 6 7 8 9
10
11 12 13 14 15
16 17
18
19 21
298.7 2100
20
14.2 28.4 42.7 56.9 71.1 85.3 99.5
113.8 128.0 142.2
151.4
170.6
184.9 199.1
213.3 227.5
241.7
256.0
270.2
284.4
100 200 300 400 500 600 700 800 900
1000 1100 1200
1300
1400 1500 1600
1700 1800
1900
2000
25 30 35
77 86 95
psi kPa kg/cm
2
C
F
“A”
“B”
“C”
“D”
23
2300
327.1
[A]
[B]
[C][D][E]
[E]
I7RS0A721006-01
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11) Check inlet port temperature-to-outlet port temperature relationship using the graph. For example, if temperature
near air inlet of HVAC unit is 30 °C (86 °F) and the one at air outlet of center ventilation louver is 17 °C (62.6 °F),
their crossing point is within acceptable range as shown in the graph. In this case, cooling performance is
satisfactory and proper.
12) If crossing point is out of acceptable range, diagnose trouble referring to the following table.
Thermometer at center duct
NOTE
If ambient temperature is approximately 30 °C (86 °F), it is possible to diagnose A/C system in detail
referring to the following table.
[A]: Temp at air outlet of center ventilation louver [C]: Humidity
[B]: Temp near air inlet of HVAC unit [D]: Acceptable range
ConditionPossible cause Correction
Crossing point is higher
than acceptable range
(“E” area) Insufficient or excessive charge of refrigerant Check refrigerant pressure.
Dirty or bent A/C evaporator fins
Clean or repair.
Air leakage from cooling (heater) unit or air duct Repair or replace.
Malfunctioning, switch over function of door in
cooling (heater) unit Repair or replace.
Compressor malfunct ion Check compressor.
Crossing point is lower
than acceptable range
(“F” area) Insufficient air volume from center duct
(Heater blower malfunction)
Check blower motor and fan.
Compressor malfunct ion Check compressor.
8 9
10 11 12 13 14
15 16 17 18 19
20
21
22
23
24
25 26
27
28
46.4 48.2 50.0 51.8 53.6 55.4 57.2 59.0 60.8 62.6 64.4
66.2 68.0
69.8
71.6
73.4
75.2
77.0
78.8 80.6
82.4
25 30 35
77 86 95
F C
C
F
“E”
“F”30 70 %
[A]
[B][C]
[D]
I7RS0A721007-01