2011 INFINITI QX56 heater

A/C UNIT ASSEMBLYHA-41
< REMOVAL AND INSTALLATION >
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A/C UNIT ASSEMBLY
Exploded ViewINFOID:0000000006276182
REMOVAL
DISASSEMBLY
1. Heater & cooling unit assembly 2. Steering member 3. Instrument stay LH
4. Instrument stay RH 5. Blower unit assembly
Refer to GI-4, "
Components" for symbols in the figure.
JMIIA0628GB
Revision: 2010 May2011 QX56

HA-42
< REMOVAL AND INSTALLATION >
A/C UNIT ASSEMBLY
HEATER & COOLING UNIT ASSEMBLY
HEATER & COOLING UNIT ASSEMBLY : Removal and InstallationINFOID:0000000006276183
CAUTION:
1. Rear heater packing 2. A/C case RH 3. Foot duct RH
4. Heater core assembly 5. Heater pipe cover 6. Evaporator pipe cover
7. Evaporator pipe assembly 8. O-ring 9. Expansion valve
10. Grommet 11. Heater packing 12. Drain hose assembly
13. A/C case lower 14. A/C cover 15. Evaporator
16. Intake sensor 17. Dfroster door 18. Upper ventirator door
19. Slide door unit 20. A/C case center 21. A/C case LH
22. Foot duct LH 23. Aspirator 24. Aspirator hose
25. In-vehicle sensor 26. Foot door LH 27. Foot door RH
28. Ventirator door 29. Ventirator packing
Refer to GI-4, "
Components" for symbols in the figure.
JMIIA0629GB
Revision: 2010 May2011 QX56

A/C UNIT ASSEMBLYHA-43
< REMOVAL AND INSTALLATION >
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Perform lubricant return operati on before each refrigeration system disassembly. However, if a large
amount of refrigerant or lubricant is detected, n ever perform lubricant return operation. Refer to HA-
22, "Perform Lubricant Return Operation".
REMOVAL
1. Use a refrigerant collecting equipment (for HF C-134a) to discharge the refrigerant. Refer to HA-20, "Recy-
cle Refrigerant". (If equipped)
2. Drain engine coolant from cooling system. Refer to CO-8, "
Draining".
3. Remove clamps, and then disconnect front heater outlet hose from heater pipe.
CAUTION:
 Some coolant may spill when heater hoses are disconnected.
 Close off the coolant inlet and outlet on the heater core (2 locations) with shop cloths.
4. Remove mounting bolt, and then disconnect low-pressure pipe and high-pressure pipe from expansion valve.
CAUTION:
Cap or wrap the joint of the A/C piping and expan sion valve with suitable material such as vinyl
tape to avoid the entry of air.
5. Remove instrument panel assembly. Refer to IP-14, "
Removal and Installation".
6. Remove steering column mounting bolt and nuts. Refer to ST-34, "
Removal and Installation".
7. Move steering column assembly to a position where it does not inhibit work.
8. Disconnect harness clips, harness connectors, ground bol ts and blackets from steering member, and then
move the vehicle harness to the position without hindrance for work.
9. Remove mounting nuts, and then remove instrument stay (RH and LH).
10. Remove A/C unit assembly mounting bolts.
11. Remove mounting bolts, and then remove steering member from the vehicle.
12. Disconnect drain hose from A/C unit assembly, and then remove A/C unit assembly from the vehicle.
13. Remove mounting bolts, and then disconnect heater & cooling unit and blower unitassembly.
INSTALLATION
Note the following items, and install in the reverse order of removal.
CAUTION:
 Replace O-rings with new ones. Then apply compressor oil to them when installing.
 Check for leakages when recharging refrigerant. Refer to HA-18, "
Leak Test".
NOTE:
Refer to CO-9, "
Refilling" when filling radiator with engine coolant.
EVAPORATOR
EVAPORATOR : Removal and InstallationINFOID:0000000006276184
REMOVAL
1. Remove heater & cooling unit assembly. Refer to HA-41, "Exploded View".
2. Remove heater core. Refer to HA-44, "
HEATER CORE : Removal and Installation".
3. Remove mounting screws, and then remove evaporator pipe cover.
4. Remove air mix door motor (RH). Refer to HAC-153, "
AIR MIX DOOR MOTOR : Removal and Installa-
tion".
5. Remove mounting screws, and then remove A/C cover.
6. Remove foot duct LH. Refer to VTL-11, "
FLOOR DUCT 1 : Removal and Installation".
7. Remove mounting screws, and then remove A/C lower case.
8. Remove intake sensor. Refer to HAC-150, "
Removal and Installation".
9. Remove evaporator assembly from heater & cooling unit assembly.
10. Remove mounting bolts, and then remove evaporator from evaporator assembly.
CAUTION:
Cap or wrap the joint of the evaporator and evaporat or pipe assembly with suitable material such as
vinyl tape to avoid the entry of air.
Revision: 2010 May2011 QX56

HA-44
< REMOVAL AND INSTALLATION >
A/C UNIT ASSEMBLY
INSTALLATION
Note the following items, and install in the reverse order of removal.
CAUTION:
 Replace O-rings with new ones. Then apply compressor oil to them when installing.
 When install the intake sensor, set the same position before replacement.
 Never rotate the bracket insertion part when removing and installing the intake sensor.
 Perform lubricant adjusting procedure af ter installing new evaporator. Refer to HA-22, "
Lubricant
Adjusting Procedure for Components Replacement Except Compressor".
HEATER CORE
HEATER CORE : Removal and InstallationINFOID:0000000006276185
REMOVAL
1. Remove heater & cooling unit assembly. Refer to HA-42, "HEATER & COOLING UNIT ASSEMBLY :
Removal and Installation".
2. Remove mounting screws, and then remove heater core pipe cover.
3. Remove mode door motor. Refer to HAC-153, "
MODE DOOR MOTOR : Removal and Installation".
4. Remove main link, foot door link and foot door lever. Refer to HAC-152, "
Exploded View".
5. Remove mounting screws, and then remove foot duct (assist side). Refer to VTL-11, "
FLOOR DUCT 1 :
Removal and Installation".
6. Pull out heater core (1) from heater & cooling unit assembly.
INSTALLATION
Note the following items, and install in the reverse order of removal.
CAUTION:
 Replace O-rings with new ones. Then apply compressor oil ti them when installing
 Check for leakages when recharging refrigerant. Refer to HA-18, "
Leak Test".
EXPANSION VALVE
EXPANSION VALVE : Removal and InstallationINFOID:0000000006276186
CAUTION:
Perform lubricant return operation before each refrigeration system disassembly. However, if a large
amount of refrigerant or lubrican t is detected, never perform lubricant return operation. Refer to HA-
22, "Perform Lubricant Return Operation".
REMOVAL
1. Use a refrigerant collecting equipment (for HF C-134a) to discharge the refrigerant. Refer to HA-20, "Recy-
cle Refrigerant".
2. Remove A/C unit assembly. Refer to HA-42, "
HEATER & COOLING UNIT ASSEMBLY : Removal and
Installation".
3. Remove mounting bolts, and then remove expansion valve. CAUTION:
Cap or wrap the joint of the evaporator pipe assembly and expansion valve with suitable material
such as vinyl tape to avoid the entry of air.
INSTALLATION
Note the following items, and install in the reverse order of removal.
JMIIA0684ZZ
Revision: 2010 May2011 QX56

REAR A/C UNITHA-47
< REMOVAL AND INSTALLATION >
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REAR A/C UNIT ASSEMBLY
REAR A/C UNIT ASSEMBLY : Removal and InstallationINFOID:0000000006276188
REMOVAL
1. Use a refrigerant collecting equipment (for HF C-134a) to discharge the refrigerant. Refer to HA-22, "Per-
form Lubricant Return Operation".
2. Drain engine coolant from cooling system. Refer to HA-22, "
Perform Lubricant Return Operation".
3. Remove rear ventilator duct upper. Refer to VTL-12, "
REAR VENTILATOR DUCT UPPER : Removal and
Installation".
4. Remove rear ventilator duct lower. Refer to VTL-12, "
REAR VENTILATOR DUCT LOWER : Removal and
Installation".
5. Remove mounting bolt, and then disconnect rear cooler unit pipe assembly from rear cooler pipe assem-
bly.
1. Rear blower harness 2. Rear blower motor 3. Rear A/C unit case RH
4. Rear evaporator pipe assembly 5. O-ring 6. Rear expantion valve assembly
7. Rear A/C cooler pipe assembly 8. Pipe bracket 9. Grommet
10. Rear cooler pipe 11. Rear heater outlet tube assembly 12. Blind cap
13. Rear heater inlet tube assembly 14. Clamp 15. Clamp
16. Shild plate 17. Bracket 18. Rear A/C unit case LH
19. Rear evapolator 20. Drain hose 21. Rear air mix door
22. Rear heater core 23. Rear heater pipe clamp 24. Rear A/C unit upper case (front)
25. Rear mode door 26. Rear A/C unit upper case (rear) 27. Air mix door harness
28. Rear intake sensor 29. Packing
Refer to GI-4, "
Components" for symbols in the figure.
JMIIA0641GB
Revision: 2010 May2011 QX56

HA-48
< REMOVAL AND INSTALLATION >
REAR A/C UNIT
CAUTION:
Cap or wrap the joint of the A/C piping with suitable material such as vinyl tape to avoid the entry
of air.
6. Remove clamps, and then disconnect rear heater pipe from rear cooler pipe assembly.
7. Remove jack from the vehicle.
8. Remove mounting bolts and nuts, and then remove rear A/C unit assembly.
INSTALLATION
Note the following items, and install in the reverse order of removal.
CAUTION:
 Replace O-rings with new ones. Then apply compressor oil to them when installing.
 Check for leakages when recharging refrigerant. Refer to HA-18, "
Leak Test".
EVAPORATOR
EVAPORATOR : Removal and InstallationINFOID:0000000006276189
REMOVAL
1. Remove rear A/C unit assembly. Refer to HA-47, "REAR A/C UNIT ASSEMBLY : Removal and Installa-
tion".
2. Disassemble rear A/C unit, and then remove rear evaporator assembly.
3. Remove mounting bolt, and then remove rear evaporator from rear evaporator assembly.
INSTALLATION
Note the following items, and install in the reverse order of removal.
CAUTION:
 Replace O-rings with new ones. Then apply compressor oil to them when installing.
 Check for leakages when recharging refrigerant. Refer to HA-18, "
Leak Test".
EVAPORATOR PIPE ASSEMBLY
EVAPORATOR PIPE ASSEMBLY : Removal and InstallationINFOID:0000000006276190
REMOVAL
1. Remove rear evaporator assembly. Refer to HA-48, "EVAPORATOR : Removal and Installation".
2. Remove mounting bolts, and then rear expansion valve from rear evaporator assembly. CAUTION:
Cap or wrap the joint of the A/C piping and rear expansion valve with suitable material such as
vinyl tape to avoid the entry of air.
3. Remove mounting bolts, and then remove evaporat or pipe assembly from evaporator assembly.
INSTALLATION
Note the following items, and install in the reverse order of removal.
CAUTION:
 Replace O-rings with new ones. Then apply compressor oil to them when installing.
 Check for leakages when recharging refrigerant. Refer to HA-18, "
Leak Test".
HEATER CORE
HEATER CORE : Removal and InstallationINFOID:0000000006276191
REMOVAL
1. Remove rear A/C unit assembly. Refer to HA-47, "REAR A/C UNIT ASSEMBLY : Removal and Installa-
tion"
2. Remove grommet from pipe bracket.
3. Remove mounting screws and then remove pipe bracket.
4. Remove mounting screw, and then heater pipe clamp.
Revision: 2010 May2011 QX56

REAR A/C UNITHA-49
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5. Pull out heater core (1) from rear A/C unit assembly.
INSTALLATION
Note the following item, and install in the reverse order of removal.
NOTE:
Refer to CO-9, "
Refilling" when filling radiator with engine coolant.
EXPANSION VALVE
EXPANSION VALVE : Removal and InstallationINFOID:0000000006276192
REMOVAL
1. Remove rear A/C unit assembly. Refer to HA-47, "REAR A/C UNIT ASSEMBLY : Removal and Installa-
tion".
2. Disassembly rear A/C unit assembly.
3. Remove mounting bolts, and then disconnect rear exp ansion valve assembly from rear evaporator pipe
assembly and rear cooler pipe assembly.
INSTALLATION
Note the following items, and install in the reverse order of removal.
CAUTION:
 Replace O-rings with new ones. Then apply compressor oil to them when installing.
 Check for leakages when recharging refrigerant. Refer to HA-18, "
Leak Test".
JMIIA0685ZZ
Revision: 2010 May2011 QX56

HAC-1
VENTILATION, HEATER & AIR CONDITIONER
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CONTENTS
HEATER & AIR CONDITIONING CONTROL SYSTEM
AUTOMATIC AIR CONDITIONING
PRECAUTION ................ ...............................
5
PRECAUTIONS .............................................. .....5
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ......
5
SYSTEM DESCRIPTION ..............................6
COMPONENT PARTS ................................... .....6
FRONT AUTOMATIC AIR CONDITIONING SYS-
TEM ........................................................................ ......
6
FRONT AUTOMATIC AIR CONDITIONING SYS-
TEM : Component Parts Location .............................
6
FRONT AUTOMATIC AIR CONDITIONING SYS-
TEM : Component Description ..................................
7
REAR AUTOMATIC AIR CONDITIONING SYS-
TEM ........................................................................ ......
8
REAR AUTOMATIC AIR CONDITIONING SYS-
TEM : Component Parts Location .............................
9
REAR AUTOMATIC AIR CONDITIONING SYS-
TEM : Component Description ................................
10
ACCS (ADVANCED CLIMATE CONTROL SYS-
TEM) ...................................................................... ....
10
ACCS (ADVANCED CLIMATE CONTROL SYS-
TEM) : Component Parts Location ..........................
11
ACCS (ADVANCED CLIMATE CONTROL SYS-
TEM) : Component Description ...............................
11
Aspirator ..................................................................12
Front Blower Motor ..................................................12
Rear Blower Motor ..................................................13
Refrigerant Pressure Sensor ...................................13
SYSTEM .............................................................14
FRONT AUTOMATIC AIR CONDITIONING SYS-
TEM ........................................................................ ....
14
FRONT AUTOMATIC AIR CONDITIONING SYS-
TEM : System Diagram ...........................................
14
FRONT AUTOMATIC AIR CONDITIONING SYS-
TEM : System Description .......................................
14
FRONT AUTOMATIC AIR CONDITIONING SYS-
TEM : Air Flow Control ............................................
15
FRONT AUTOMATIC AIR CONDITIONING SYS-
TEM : Air Inlet Control .............................................
16
FRONT AUTOMATIC AIR CONDITIONING SYS-
TEM : Air Outlet Control ..........................................
17
FRONT AUTOMATIC AIR CONDITIONING SYS-
TEM : Compressor Control ......................................
17
FRONT AUTOMATIC AIR CONDITIONING SYS-
TEM : Door Control ..................................................
18
FRONT AUTOMATIC AIR CONDITIONING SYS-
TEM : Temperature Control .....................................
21
FRONT AUTOMATIC AIR CONDITIONING SYS-
TEM : Fail-safe ........................................................
21
REAR AUTOMATIC AIR CONDITIONING SYS-
TEM ........................................................................ ....
22
REAR AUTOMATIC AIR CONDITIONING SYS-
TEM : System Diagram ...........................................
23
REAR AUTOMATIC AIR CONDITIONING SYS-
TEM : System Description .......................................
23
REAR AUTOMATIC AIR CONDITIONING SYS-
TEM : Air Flow Control ............................................
24
REAR AUTOMATIC AIR CONDITIONING SYS-
TEM : Air Outlet Control ..........................................
25
REAR AUTOMATIC AIR CONDITIONING SYS-
TEM : Door Control ..................................................
26
REAR AUTOMATIC AIR CONDITIONING SYS-
TEM : Temperature Control .....................................
27
ACCS (ADVANCED CLIMATE CONTROL SYS-
TEM) ....................................................................... ....
27
ACCS (ADVANCED CLIMATE CONTROL SYS-
TEM) : System Diagram ..........................................
28
ACCS (ADVANCED CLIMATE CONTROL SYS-
TEM) : System Description ......................................
28
Revision: 2010 May2011 QX56