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Nissan Cube. Manual - part 545

HAC-18

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONING]

AUTOMATIC AIR CONDITIONING SYSTEM

AIR OUTLET CONTROL

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

mode door position depending on a target air mix door 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.

TEMPERATURE CONTROL

• When ignition switch is in the ON position, A/C auto amp. always

automatically controls temperature regardless of air conditioner
operational state.

• A/C auto amp. calculates the target air mix door opening angle

depending on set temperature, in-vehicle temperature, ambient
temperature, and sunload.

• Air mix door is controlled depending on the comparison of current

air mix door opening angle and target air mix door opening angle.

• Regardless of in-vehicle temperature, ambient temperature, and

sunload, air mix door is fixed at the fully cold position when set
temperature is 18

C (60

F), and at the fully hot position when set

temperature is 32

C (90

F).

AIR INLET FUNCTION

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

inlet (fresh air intake, 20% fresh air intake, or recirculation)
depending on set temperature, in-vehicle temperature, and ambi-
ent temperature.

• Air inlet is fixed to 80% FRE, only when the conditions are satisfied

as follows:

- Air inlet is FOOT or D/F
- Ambient temperature is 2

C (36

F) or less

- Maximum fan speed

AIR FLOW CONTROL

Description

• A/C auto amp. changes duty ratio of blower motor drive signal and controls air flow continuously. When air

flow is increased, duty ratio of blower motor drive signal gradually increases to prevent a sudden increase in
air flow.

• In addition to manual control and automatic control, air flow control is compose of starting fan speed control,

low coolant temperature starting control, high in-vehicle temperature starting control, and blower speed con-
trol at door motor operation.

Automatic Air Flow Control

• A/C auto amp. decides target air flow depending on target air mix door opening angle.

A/C switch

The compressor control (switch indicator) is turned between ON

⇔

OFF by pressing this switch each

time only when blower fan is activated.
NOTE:
• When blower fan is inactivation, compressor control can not be turned ON.
• When mode position is D/F or DEF, A/C switch is turned ON forcibly.

Rear window defogger
switch

Rear window defogger (switch indicator) is turned between ON

⇔

OFF by pressing this switch each

time.
Rear window defogger system details. Refer to

DEF-4, "System Description"

JSIIA1334GB

JPIIA0633GB

JPIIA0634GB

AUTOMATIC AIR CONDITIONING SYSTEM

HAC-19

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONING]

HAC

• A/C auto amp. changes duty ratio of blower motor drive signal and controls air flow continuously so that air

flow matches to target air flow.

• When air outlet is VENT or B/L, the minimum air flow is changed

depending on sunload.

Starting Fan Speed Control

When blower motor is activated, A/C auto amp. gradually increases duty ratio of blower fan drive signal to pre-
vent a sudden increase in discharge air flow. (T

1 –

= approximately 10 seconds)

NOTE:
Do not perform the starting air flow control when the discharge outlet
is set to DEF.

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 blower motor
activation for the maximum 150 seconds depending on target air mix
door opening angle. After this, blower fan drive signal is increased
gradually, and blower motor is activated.

Fan speed Control at Door Motor Operation

When mode door motor is activated while air flow is more than the specified value, A/C auto amp. reduces
temporarily fan speed so that mode door moves smoothly.

High In-vehicle Temperature Starting Control

When evaporator temperature is high [intake air temperature sensor value is 35

C (95

F) or more], to prevent

a hot discharged air flow, A/C auto amp. suspends blower motor activation for approximately 3 seconds so
that evaporator is cooled by refrigerant.

COMPRESSOR CONTROL

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 BCM.

• BCM transmits 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, throttle opening angle sensor signal, and others). And transmits A/C relay control signal to
IPDM E/R via CAN communication.

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

JPIIA1564GB

JPIIA1655GB

JSIIA1529GB

HAC-20

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONING]

AUTOMATIC AIR CONDITIONING SYSTEM

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 (31.8 kg/cm

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

• 2.74 MPa (27.9 kg/cm

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

• 0.14 MPa (1.4 kg/cm

, 20 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 evaporator surface temperature is
2

C (36

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

pressor OFF, and stops the compressor.
When the air temperature returns to 3.5

C (38

F) or more, the com-

pressor 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 Conditioner Cut Control

When the engine is running in excessively high load condition, ECM requests IPDM E/R to turn A/C relay OFF,
and stops the compressor. Refer to

EC-58, "System Description"

for details.

DOOR MOTOR CONTROL

Mode Door Motor

The A/C auto amp. receives data from each sensors. When a drive signal is input from A/C auto amp. to door
motor, a step motor built into the door motor rotates according to the drive signal, and then stops at the posi-
tion of target door.

Air Mix Door Motor

SJIA0802E

SJIA0971E

AUTOMATIC AIR CONDITIONING SYSTEM

HAC-21

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONING]

HAC

Intake Door Motor

The A/C auto amp. receives data from each sensor, and converts
them to control signal. The A/C auto amp. sends the control signal to
Intake door motor. When intake door motor receives the control sig-
nal, intake door is moved to appropriate position by PBR opening
angle indication signal.

SWITCHES AND THEIR CONTROL FUNCTIONS

SJIA0970E

JPIIA1656GB

Content .. 543 544 545 546 ..