Nissan Xterra. Manual - part 452

HAC-6

< SYSTEM DESCRIPTION >

[MANUAL AIR CONDITIONER]

FUNCTION INFORMATION

PASSENGER COMPARTMENT

⇒

:Front

1.

Front air control M50

2.

Intake sensor M146

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FUNCTION INFORMATION

HAC-7

< SYSTEM DESCRIPTION >

[MANUAL AIR CONDITIONER]

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D

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F

G

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HAC

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3.

Intake door motor M58

4.

Variable blower control M121

5.

Mode door motor M142

6.

Air mix door motor M147

HAC-8

< SYSTEM DESCRIPTION >

[MANUAL AIR CONDITIONER]

REFRIGERATION SYSTEM

REFRIGERATION SYSTEM

Refrigerant Cycle

INFOID:0000000009482457

REFRIGERANT FLOW

The refrigerant flows in the standard pattern, that is, through the compressor, the condenser with liquid tank,

through the front evaporator, and back to the compressor. The refrigerant evaporation through the evaporator

coil is controlled by the front externally equalized expansion valve, located inside the front 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.

WJIA1482E

MANUAL AIR CONDITIONER SYSTEM

HAC-9

< SYSTEM DESCRIPTION >

[MANUAL AIR CONDITIONER]

C

D

E

F

G

H

J

K

L

M

A

B

HAC

N

O

P

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

AWIIA1398GB

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