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Nissan Sentra. Manual - part 540

HAC-8

< PREPARATION >

[AUTOMATIC AIR CONDITIONER]

PREPARATION

PREPARATION

Special Service Tool

INFOID:0000000009757615

The actual shape of the tools may differ from those illustrated here.

Commercial Service Tool

INFOID:0000000009757616

Tool number
(TechMate No.)
Tool name

Description

—

(J-46534)
Trim Tool Set

Removing trim components

AWJIA0483ZZ

Tool name

Description

Power tool

Loosening nuts, screws and bolts

PIIB1407E

COMPONENT PARTS

HAC-9

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONER]

HAC

SYSTEM DESCRIPTION

COMPONENT PARTS

Component Part Location

INFOID:0000000009757617

ALIIA0703ZZ

HAC-10

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONER]

COMPONENT PARTS

Component Description

INFOID:0000000009757618

ECM

IPDM E/R

BCM (view with instrument panel re-
moved)

A/C auto amp. (view with A/C switch
assembly removed)

A/C switch assembly

A/C Compressor

Refrigerant pressure sensor (view
with front bumper fascia removed)

Ambient sensor

Sunload sensor

10. In-vehicle sensor

11. Blower motor relay

12. Blower motor (view with front A/C

assembly removed from vehicle)

13. Air mix door motor RH

14. Mode door motor

15. Intake door motor

16. Air mix door motor LH

17. Intake sensor

18. Variable blower control

ALIIA0704ZZ

Component

Description

A/C auto amp.

A/C auto amp. controls front automatic air conditioning system by inputting and calculating signals
from each sensor and each switch.

A/C Compressor

Vaporized refrigerant is drawn into the A/C compressor from the evaporator, where it is compressed
to a high pressure, high temperature vapor. The hot, compressed vapor is then discharged to the con-
denser.

A/C switch assembly

The A/C switch assembly controls the operation of the A/C and heating system based on inputs from
the temperature control knob, the mode switches, the blower control dial, the ambient temperature
sensor, the intake sensor, and inputs received from the ECM across the CAN. Diagnosis of the A/C
switch assembly can be performed using the CONSULT.

Air mix door motor LH

The air mix door controls the mix of hot or cold air that enters the ventilation system. It is controlled
by the A/C auto amp. based on the position of the temperature dial. The air mix door motor LH re-
ceives position commands from the A/C auto amp.

Air mix door motor RH

The air mix door controls the mix of hot or cold air that enters the ventilation system. It is controlled
by the A/C auto amp. based on the position of the temperature dial. The air mix door motor RH re-
ceives position commands from the A/C auto amp.

Ambient sensor

The ambient sensor measures the temperature of the air surrounding the vehicle. The sensor uses a
thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor
decreases as temperature increases.

BCM

The BCM receives the fan ON and A/C ON signals from the A/C auto amp. and sends a compressor
ON request to the ECM.

Blower motor

The blower motor varies the speed at which the air flows through the ventilation system.

Blower motor relay

The blower motor relay controls the flow of current to fuse 20, 21 and 22 in the Fuse Block (J/B). The
relay is connected directly to ground, and is energized when the ignition switch is in the ON or START
position.

COMPONENT PARTS

HAC-11

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONER]

HAC

ECM

The ECM sends a compressor ON request to the IPDM E/R based on the status of engine operation
and load as well as refrigerant pressure information. If all the conditions are met for A/C operation,
the ECM transmits the compressor ON request to the IPDM E/R. The ECM shares the refrigerant
pressure sensor signal, engine RPM, and engine coolant temperature with the A/C auto amp. via
CAN communication line.

Fuse Block (J/B)

Located in the passenger compartment, behind the left lower IP, the Fuse Block (J/B) contains the
blower motor relay and several fuses required for the air conditioner control system.

Intake door motor

The intake door motor controls the position of the intake door. Fresh air is allowed to enter the cabin
in one position, and recirculated inside air is allowed to enter in the other position. At times the A/C
auto amp. may command partial fresh or recirculation based on evaporator or coolant temperatures.
The intake door motor receives position commands from the A/C auto amp. and reports actual door
position back via an LCU (Local Control Unit) installed inside the motor. The LCU reads the door po-
sition from a Position Balanced Resistor (PBR), also part of the motor, and returns that information to
the A/C auto amp. The LCU switches the polarity of the circuits connected to the DC motor to drive
the motor forward or backward as requested by the A/C auto amp.

Intake sensor

The intake sensor measures the temperature of the front evaporator fins. The sensor uses a ther-
mistor which is sensitive to the change in temperature. The electrical resistance of the thermistor de-
creases as temperature increases.

In-vehicle sensor

In-vehicle sensor measures temperature of intake air that flows through aspirator to passenger room.
The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resis-
tance of the thermistor decreases as temperature increases.

IPDM E/R

Refer to

PCS-7, "RELAY CONTROL SYSTEM : System Description"

Mode door motor

The mode door controls the direction the conditioned air passes through the ventilation system.
Through a series of levers and gears, the mode door controls the defrost door, the foot door, and the
vent door. There are 5 preset positions: VENT, B/L, FOOT, D/F, and DEF. The FOOT position can be
set to allow some airflow through to the defroster vent, or to completely block the defroster vent using
the CONSULT. The mode door motor receives position commands from the A/C auto amp.

Refrigerant pressure sensor

Refer to

EC-29, "Refrigerant Pressure Sensor"

Sunload sensor

Sunload sensor measures sunload amount. This sensor is a dual system so that sunload for driver
side and passenger side are measured separately. This sensor converts sunload amount to voltage
signal by photodiode and transmits to A/C auto amp.

Component

Description

Content .. 538 539 540 541 ..