Nissan Altima L32. Manual - part 834

HAC-110

< FUNCTION DIAGNOSIS >

[MANUAL AIR CONDITIONER]

AIR CONDITIONER CONTROL

AIR CONDITIONER LAN CONTROL SYSTEM

The LAN (Local Area Network) system consists of front air control, mode door motor, air mix door motor and

intake door motor.

A configuration of these components is shown in the figure below.

SYSTEM CONSTRUCTION

A small network is constructed between the front air control, mode door motor, air mix door motor and intake

door motor. The front air control and motors are connected by data transmission lines and motor power supply

lines. The LAN network is built through the ground circuits of each door motors.

Addresses, motor opening angle signals, motor stop signals and error checking messages are all transmitted

through the data transmission lines connecting the front air control and each door motor.

The following functions are contained in LCUs built into the mode door motor, the air mix door motor and the

intake door motor.

• Address

• Motor opening angle signals

• Data transmission

• Motor stop and drive decision

• Opening angle sensor (PBR function)

• Comparison

• Decision (Front air control indicated value and motor opening angle comparison)

Operation

AWIIA0041GB

WJIA0876E

WJIA0883E

AIR CONDITIONER CONTROL

HAC-111

< FUNCTION DIAGNOSIS >

[MANUAL AIR CONDITIONER]

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The front air control receives data from each of the sensors. The front air control sends mode door, air mix

door and intake door opening angle data to the mode door motor LCU, air mix door motor LCUs and intake

door motor LCU.

The mode door motor, air mix door motor and intake door motor read their respective signals according to the

address signal. Opening angle indication signals received from the front air control and each of the motor posi-

tion sensors is compared by the LCUs in each door motor with the existing decision and opening angles. Sub-

sequently, HOT/COLD, DEF/VENT and FRE/REC operation is selected. The new selection data is returned to

the front air control.

Transmission Data and Transmission Order

Front air control data is transmitted consecutively to each of the doors motor following the form shown in figure

below.

START:

• Initial compulsory signal is sent to each of the door motors.

ADDRESS:

• Data sent from the front air control are selected according to data-based decisions made by the mode door

motor, air mix door motors and intake door motor.

• If the addresses are identical, the opening angle data and error check signals are received by the door motor

LCUs. The LCUs then make the appropriate error decision. If the opening angle data have no error, door

control begins.

• If an error exists, the received data are rejected and corrected data received. Finally, door control is based

upon the corrected opening angle data.

OPENING ANGLE:

• Data that shows the indicated door opening angle of each door motor.

ERROR CHECK:

• In this procedure, transmitted and received data is checked for errors. Error data are then compiled. The

error check prevents corrupted data from being used by the mode door motor, the air mix door motor and the

intake door motor. Error data can be related to the following symptoms.

- Malfunction of electrical frequency

- Poor electrical connections

- Signal leakage from transmission lines

- Signal level fluctuation

STOP SIGNAL:

WJIA0878E

HAC-112

< FUNCTION DIAGNOSIS >

[MANUAL AIR CONDITIONER]

AIR CONDITIONER CONTROL

• At the end of each transmission, a stop operation, in-operation, or internal malfunction message is delivered

to the front air control. This completes one data transmission and control cycle.

AIR MIX DOOR CONTROL 

The air mix door is controlled by the front air control based on input from the temperature dial setting--

A/C SWITCH 

The air conditioner switch controls the A/C system. When the switch is pressed with the fan ON, the compres-

sor will turn ON. The indicator will also illuminate.

TEMPERATURE CONTROL DIAL 

Increases or decreases the set temperature.

BLOWER CONTROL DIAL

Manually controls the blower speed.

In the off position, the compressor and blower are OFF, the intake door is set to the outside air position.

RECIRCULATION (

) SWITCH 

OFF position: Outside air is drawn into the passenger compartment.

ON position: Interior air is recirculated inside the vehicle.

DEFROSTER SWITCH

Position the air mode doors to the defrost position. Also positions the intake doors to the outside air position.

The compressor remains ON until the ignition is turned OFF.

MODE SWITCHES

Controls the air discharge through control of mode door, also controls MAX A/C function.

REAR WINDOW DEFOGGER SWITCH

This switch turns the rear window defogger ON and OFF.

WJIA0882E

AIR CONDITIONER CONTROL

HAC-113

< FUNCTION DIAGNOSIS >

[MANUAL AIR CONDITIONER]

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MAGNET CLUTCH CONTROL

When A/C switch is pressed, or the defroster mode switch is pressed, the front air control outputs a compres-

sor ON signal to the BCM.

The BCM then sends a compressor ON signal to the ECM, via CAN communication line. The ECM judges

whether compressor can be turned ON, based on each sensor status (refrigerant-pressure sensor signal,

throttle angle, etc.). If it judges compressor can be turned ON, it sends compressor ON signal to IPDM E/R,

via CAN communication.

Upon receipt of compressor ON signal from ECM, IPDM E/R turns A/C relay ON to operate compressor.

Component Part Location

INFOID:0000000004498263

ENGINE COMPARTMENT

Refer to 

HAC-104, "Component Part Location"

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PASSENGER COMPARTMENT

Refer to 

HAC-104, "Component Part Location"

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Component Description

INFOID:0000000004498264

Refer to 

HAC-106, "Component’s Role"

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AWIIA0042GB