Nissan Frontier D40. Manual - part 744

FUNCTION INFORMATION

HAC-79

< FUNCTION DIAGNOSIS >

[MANUAL A/C (TYPE 2)]

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PASSENGER COMPARTMENT

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:Front

1.

Front air control M49

2.

Intake sensor M146

3.

Intake door motor M58

4.

Front blower motor resistor M122

5.

Mode door motor M142

6.

Air mix door motor M147

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HAC-80

< FUNCTION DIAGNOSIS >

[MANUAL A/C (TYPE 2)]

REFRIGERATION SYSTEM

REFRIGERATION SYSTEM

Refrigerant Cycle

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REFRIGERANT FLOW

The refrigerant flows in the standard pattern. Refrigerant flows through the compressor, condenser, liquid tank,
expansion valve, evaporator, and back to the compressor. The refrigerant evaporation through the evaporator
coil is controlled by an externally equalized expansion valve, located inside the evaporator case.

FREEZE PROTECTION

The compressor cycles on and off to maintain the evaporator temperature within a specified range. When the
evaporator coil temperature falls below a specified point, the intake sensor interrupts the compressor opera-
tion. When the evaporator coil temperature rises above the specification, the intake sensor allows compressor
operation.

Refrigerant System Protection

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REFRIGERANT PRESSURE SENSOR

The refrigerant system is protected against excessively high- or low-pressures by the refrigerant pressure sen-
sor, located on the condenser. If the system pressure rises above or falls below the specifications, the refriger-
ant pressure sensor detects the pressure inside the refrigerant line and sends a voltage signal to the ECM.
The ECM de-energizes the A/C relay to disengage the magnetic compressor clutch when pressure on the high
pressure side detected by refrigerant pressure sensor is over about 2,746 kPa (28 kg/cm

2

, 398 psi), or below

about 120 kPa (1.22 kg/cm

2

, 17.4 psi).

PRESSURE RELIEF VALVE

The refrigerant system is also protected by a pressure relief valve, located in the rear head of the compressor.
When the pressure of refrigerant in the system increases to an abnormal level [more than 2,990 kPa (30.5 kg/
cm

2

, 433.6 psi)], the release port on the pressure relief valve automatically opens and releases refrigerant into

the atmosphere.

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MANUAL AIR CONDITIONER SYSTEM

HAC-81

< FUNCTION DIAGNOSIS >

[MANUAL A/C (TYPE 2)]

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MANUAL AIR CONDITIONER SYSTEM

Control System Diagram

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CONTROL SYSTEM

The control system consists of input sensors, switches, the front air control (microcomputer) and outputs.
The relationship of these components is shown in the figure below:

Control System Description

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CONTROL OPERATION

Front air control

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HAC-82

< FUNCTION DIAGNOSIS >

[MANUAL A/C (TYPE 2)]

MANUAL AIR CONDITIONER SYSTEM

TEMPERATURE CONTROL DIAL (TEMPERATURE CONTROL)

Increases or decreases the set temperature.

RECIRCULATION (

) SWITCH

• When REC switch is ON, REC switch indicator turns ON, and air inlet is set to REC.
• When REC switch is turned OFF, or when compressor is turned from ON to OFF, REC switch is automati-

cally turned OFF. REC mode can be re-entered by pressing REC switch again.

• REC switch is not operated when DEF switch is turned ON, or at the D/F or FOOT position.

REAR WINDOW DEFOGGER SWITCH (IF EQUIPPED)

When switch is ON, rear window is defogged.

OFF SWITCH (BLOWER SPEED SET TO 0)

The compressor and blower are OFF.

A/C SWITCH (IF EQUIPPED)

The compressor is ON or OFF.
(Pressing the A/C switch will turn off the A/C switch and compressor.)

MODE DIAL

Controls the air discharge outlets.

FRONT BLOWER CONTROL DIAL

Manually controls the four blower speeds.

MAGNET CLUTCH CONTROL

When the A/C switch is pressed, or the mode dial is turned to the DEF or D/F position, the front air control out-
puts a compressor ON signal to BCM.
The BCM then sends a compressor ON signal to ECM, via CAN communication line.
ECM judges whether compressor can be turned ON, based on each sensor status (refrigerant pressure sen-
sor signal, throttle angle sensor, etc.). If it judges compressor can be turned ON, it sends compressor ON sig-
nal to IPDM E/R, via CAN communication line.
Upon receipt of compressor ON signal from ECM, IPDM E/R turns air conditioner relay ON to operate com-
pressor.

Discharge Air Flow

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1.

Temperature control dial

2.

Blower control dial

3.

A/C switch (if equipped)

4.

Rear window defogger switch (if 
equipped)

5.

Recirculation switch

6.

Mode dial

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