Infiniti G35 (V35) Sedan. Manual - part 763

HAC-24

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

AUTOMATIC AIR CONDITIONER SYSTEM

Preset Switch

MODE Switch

The air discharge outlets is controlled with these switches.

Temperature Control Dial (Potentio Temperature Control)

The set temperature is increased or decreased with this dial.

AUTO Switch 

• The compressor, intake doors, air mix doors, mode doors and blower speed are automatically controlled so

that the in-vehicle temperature will reach, and be maintained at the set temperature selected by the operator.

• When pressing AUTO switch, air inlet, air outlet, fan speed, and discharge air temperature are automatically

controlled.

Defroster (DEF) Switch

Mode doors are set to the defrost position with this switch. Also, intake doors are set to the outside air position,
and compressor turns ON.

A/C Switch

Compressor is ON or OFF with this switch.
(Pressing the A/C switch when the A/C switch is ON will turn OFF the A/C switch and compressor.)

FAN Control Dial

The blower speed is manually controlled with this dial. Seven speeds are available for manual control (as
shown on the display screen).

OFF Switch

Compressor and blower are OFF, intake doors and the mode doors are automatically controlled.

Rear Window Defogger Switch

When illumination is ON, rear window is defogged.

Intake Switch

• When intake switch is ON, FRE LED turns ON, and air inlet is fixed to FRE.
• When press intake switch again, REC LED turns ON, and air inlet is fixed to REC.
• When intake switch is pressed for approximately 1.5 seconds or longer, FRE and REC LEDs blink twice.

Then, automatic control mode is entered. Inlet status is displayed by LED even during automatic controlled.

• When FRE LED is turned ON, shifting mode position to D/F or DEF, or when compressor is turned from ON

to OFF, intake switch is automatically turned OFF (fixed to FRE mode). REC mode can be re-entered by
pressing intake switch again, and then compressor is turned ON. (Except D/F or DEF position)

JSIIA0001GB

AUTOMATIC AIR CONDITIONER SYSTEM

HAC-25

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

C

D

E

F

G

H

J

K

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M

A

B

HAC

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P

DISCHARGE AIR FLOW

JSIIA0077GB

HAC-26

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

AUTOMATIC AIR CONDITIONER SYSTEM

SWITCHES AND THEIR CONTROL FUNCTION

AIR CONDITIONER LAN CONTROL SYSTEM

The LAN (Local Area Network) system consists of unified meter and A/C amp., mode door motor, air mix door
motor and intake door motor.
A configuration of these components is shown in the figure below.

JSIIA0115GB

JSIIA0079GB

SJIA0262E

AUTOMATIC AIR CONDITIONER SYSTEM

HAC-27

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

C

D

E

F

G

H

J

K

L

M

A

B

HAC

N

O

P

SYSTEM CONSTRUCTION

A small network is constructed between the unified meter and A/C amp., mode door motor, air mix door motor
and intake door motor. The unified meter and A/C amp. 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 motor.
Addresses, motor opening angle signals, motor stop signals and error checking messages are all transmitted
through the data transmission lines connecting the unified meter and A/C amp. 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 (Unified meter and A/C amp. indicated value and motor opening angle comparison)

Operation

The unified meter and A/C amp. receives data from each of the sensors. The unified meter and A/C amp.
sends mode door, air mix door and intake door opening angle data to the mode door motor LCU, air mix door
motor LCU 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 unified meter and A/C amp. and each of
the motor position sensors is compared by the LCUs in each door motor with the existing decision and open-
ing angles. Subsequently, HOT/COLD, DEF/VENT and FRE/REC operation is selected. The new selection
data is returned to the unified meter and A/C amp.

Transmission Data and Transmission Order

Unified meter and A/C amp. data is transmitted consecutively to each of the doors motor following the form
shown in the figure below.

START:

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

ADDRESS:

• Data sent from the unified meter and A/C amp. 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.

JSIIA0116GB

JSIIA0117GB