Nissan Pathfinder. Manual - part 690

SYSTEM

HAC-21

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONING]

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• When front blower motor is activated, A/C auto amp. gradually

increases duty ratio of front blower motor control signal to prevent

a sudden increase in discharge air flow.

• It takes approximately 8 seconds for air flow to reach HI from LOW. 

LOW COOLANT TEMPERATURE STARTING CONTROL

If the engine coolant temperature is 56

°C (133°F) or less, to prevent

a cold discharged air flow, A/C auto amp. suspends front blower

motor activation for the maximum 150 seconds depending on target

air mix door (front) opening angle. After this, front blower motor con-

trol signal is increased gradually, and front blower motor is activated.

HIGH IN-VEHICLE TEMPERATURE STARTING CONTROL

When front evaporator fin temperature is high [intake sensor value is 35

°C (95°F) or more], to prevent a hot

discharged air flow, A/C auto amp. suspends front blower motor activation for approximately 3 seconds so that

front evaporator is cooled by refrigerant. 

FAN SPEED CONTROL AT DOOR MOTOR OPERATION

When mode door motor (front) is activated while air flow is more than the specified value, A/C auto amp.

reduces fan speed temporarily so that mode door (front) moves smoothly. 

FRONT AUTOMATIC AIR CONDITIONING SYSTEM : Air Inlet Control

INFOID:0000000009176785

The intake door is automatically controlled by the temperature set-

ting, ambient temperature, in-vehicle temperature, intake tempera-

ture, amount of sunload and ON/OFF operation of the compressor.

Intake door automatic control selects FRE, 20% FRE, or REC

depending on a target air mix door (front) opening angle, based on

in-vehicle temperature, ambient temperature, and sunload.

FRONT AUTOMATIC AIR CONDITIONING SYSTEM : Air Outlet Control

INFOID:0000000009176786

• While air outlet is in automatic control, A/C auto amp. selects the

mode door (front) position depending on a target air mix door

(front) angle and outlet air temperature calculated from sunload.

• If ambient temperature is excessively low, D/F is selected to pre-

vent windshield fogging when air outlet is set to FOOT.

JMIIA0736GB

JMIIA0737GB

JMIIA0732GB

JMIIA0730GB

HAC-22

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONING]

SYSTEM

FRONT AUTOMATIC AIR CONDITIONING SYSTEM : Compressor Control

INFOID:0000000009176787

DESCRIPTION

• When the compressor activation condition is satisfied while blower motor is activated, A/C auto amp. trans-

mits A/C ON signal and blower fan ON signal to ECM via CAN communication.

• ECM judges that the compressor can be activated depending on each sensors state (refrigerant pressure

sensor signal and others) and transmits A/C compressor request signal to IPDM E/R via CAN communica-

tion.

• IPDM E/R turns A/C relay ON and activates the compressor depending on request from ECM.

COMPRESSOR PROTECTION CONTROL AT PRESSURE MALFUNCTION

When high-pressure side value that is detected by refrigerant pressure sensor is as per the following state,

ECM requests IPDM E/R to turn A/C relay OFF and stops the compressor.
• 3.12 MPa (31.82 kg/cm

2

, 452.4 psi) or more (When the engine speed is less than 1,500 rpm)

• 2.74 MPa (27.95 kg/cm

2

, 397.3 psi) or more (When the engine speed is 1,500 rpm or more)

• 0.14 MPa (1.43 kg/cm

2

, 20.3 psi) or less

COMPRESSOR OIL CIRCULATION CONTROL

When the engine starts while the engine coolant temperature is 56

°C (133°F) or less, ECM activates the com-

pressor for approximately 6 seconds and circulates the compressor lubricant once.

LOW TEMPERATURE PROTECTION CONTROL

• When intake sensor detects that front evaporator fin temperature is

2.5

°C (37°F) or less, A/C auto amp. requests ECM to turn com-

pressor OFF, and stops the compressor.

• When the front evaporator fin temperature returns to 5.0

°C (41°F)

or more, the compressor is activated.

OPERATING RATE CONTROL

When set temperature is other than fully cold or air outlet is “VENT”, “B/L” or “FOOT” A/C auto amp. controls

the compressor activation depending on ambient temperature.

AIR CONDITIONING CUT CONTROL

When set engine is running is excessively high load condition, ECM requests IPDM E/R to turn A/C relay OFF,

and stops the compressor. Refer to 

EC-36, "AIR CONDITIONING CUT CONTROL : System Description"

 for

details.

JMIIA0742GB

SYSTEM

HAC-23

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONING]

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FRONT AUTOMATIC AIR CONDITIONING SYSTEM : Door Control

INFOID:0000000009176788

DOOR MOTOR CONTROL

• LCU (Local Control Unit) is built into each door motor, and detects door position by PBR (Potentio Balance

Resistor). 

• A/C auto amp. communicates with each LCU via communication line and receives each door position feed-

back signal from each LCU.

• Each LCU controls each door to the appropriate position depending on the control signal from A/C auto amp. 

• Each LCU transmits the signal of door movement completion to A/C auto amp., when the door movement is

completed.

SWITCH AND THEIR CONTROL FUNCTION

ALIIA0580GB

JMIIA1778ZZ

HAC-24

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONING]

SYSTEM

*: Inlet status is displayed by indicator during activating automatic control

AIR DISTRIBUTION

1.

Intake door

2.

Front blower motor

3.

In-cabin microfilter

4.

Front evaporator

5.

Air mix door (front)

6.

Front heater core

7.

Foot door

8.

Ventilator door

9.

Defroster door

10. Max. cool door

Fresh air

Recirculation air

Discharge air

Defroster

Center ventilator

Side ventilator

Front foot

Rear foot

Switch position

Door position

Mode door (front)

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 do

or

Air mix door (front)

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(Driver side)

(P

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AUTO switch

AUTO

MODE switch

A

A

A

A

—

—

—

B

B

A

B

C

C

B

B

C

B

B

B

DEF switch

C

A

C

C

Intake switch

*

—

—

—

—

A

B

Temperature control 
switch (Driver side)

DUAL 
switch: 
OFF

Full cold

[18

°C (60°F)]

—

A

18.5

°C – 31.5°C

(61

°F – 89 °F)

AUTO

Full hot

[32

°C (90°F)]

B

Temperature control 
switch (Driver side)

DUAL 
switch: 
ON

Full cold

[18

°C (60°F)]

A

—

18.5

°C – 31.5°C

(61

°F – 89 °F)

AUTO

Full hot

[32

°C (90°F)]

B

Temperature control 
switch (Passenger 
side)

Full cold

[18

°C (60°F)]

—

A

18.5

°C – 31.5°C

(61

°F – 89 °F)

AUTO

Full hot

[32

°C (90°F)]

B

ON·OFF switch

OFF

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B

B

B

—