Nissan GT-R. Manual - part 163

HAC-14

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONER]

AIR MIX DOOR CONTROL SYSTEM

• The A/C auto amp. always automatically controls the temperature

regardless of the operating condition of air conditioner when the
ignition switch is ON. 

• The A/C auto amp. performs the set temperature correction when

the target temperature is set with the temperature control dial of
the preset switch and decides the air mix door position. 

• Based on the target air mix door position and the current air mix

door position, it controls the air mixture door to always become the
most suitable air mix door position. 

• The air mix door is fixed to the full-cold position when the set tem-

perature is set to 18.0

°

C (60

°

F) and it is fixed to the full-hot posi-

tion when the set temperature is set to 32.0

°

C (90

°

F).

JPIIA0633GB

INTAKE DOOR CONTROL SYSTEM

HAC-15

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONER]

C

D

E

F

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INTAKE DOOR CONTROL SYSTEM

System Diagram

INFOID:0000000009163977

System Description

INFOID:0000000009163978

The intake doors are automatically controlled by the temperature setting, ambient temperature, in-vehicle tem-
perature, intake temperature, amount of sunload and ON/OFF operation of the compressor.

SYSTEM OPERATION

• The A/C auto amp. receives data from each of the sensors.
• The A/C auto amp. sends air mix door, mode door and intake door opening angle data to the air mix door

motor LCUs, mode door motor LCU and intake door motor LCU.

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

the address signal. Opening angle indication signals received from the A/C auto amp. and each of the motor
position sensors are compared by the LCUs in each door motor with the existing decision and opening
angles.

• Subsequently, HOT/COLD, DEF/VENT and FRE/REC operation is selected. The new selection data are

returned to the A/C auto amp.

• The intake door control judges intake door position based on the ambient temperature, the intake air temper-

ature and the in-vehicle temperature. When shifting mode position D/F, when the DEF or OFF switches are
pressed, or when A/C switch is OFF, the A/C auto amp. sets the intake door at the FRE position.

Door Motor Circuit

JSIIA1546GB

JSIIA1133GB

HAC-16

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONER]

INTAKE DOOR CONTROL SYSTEM

INTAKE DOOR CONTROL SPECIFICATION

• Intake door position is basically fixed at FRE when FRE indicator

of FRE switch is ON or DEF switch is ON.

• Intake door position is basically fixed at REC when REC indicator

of REC switch is ON.

• Intake door automatic control selects FRE, 20 – 80% FRE, or REC

depending on a target air mix door opening angle, based on in-
vehicle temperature, ambient temperature, and sunload amount.

JSIIA1337GB

BLOWER MOTOR CONTROL SYSTEM

HAC-17

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONER]

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BLOWER MOTOR CONTROL SYSTEM

System Diagram

INFOID:0000000009163979

System Description

INFOID:0000000009163980

SYSTEM OPERATION

• For air flow, the manual selection (1-7 speed) with the fan control dial has priority. 
• If the AUTO switch is pressed or if the DEF switch is pressed while in the OFF condition, it changes to the

automatic control by A/C auto amp. 

• When increasing the air flow, it changes the duty ratio of blower fan motor drive signal to prevent the air flow

from suddenly increasing. 

• There are the following types of air flow control: starting air flow control, starting air flow control at low cool-

ant temperature, starting air flow control at high interior air temperature, air flow control at door motor opera-
tion, and air flow control at voice recognition in addition to manual control, normal automatic air flow control. 

AIR FLOW CONTROL

Automatic Air Flow Control

• When the target temperature is set by the temperature control dial of preset switch, the A/C auto amp. per-

forms the calculation and decides the target air flow according to the signal from each sensor. 

• The A/C auto amp. changes the duty ratio of the blower motor control signal and controls the air flow contin-

uously so that the air flow becomes the target air flow. 

• The minimum air flow will change according to the sunload when

the air discharge outlet is VENT or B/L. 

Starting Air Flow Control

• When starting the automatic control of air flow, the system gradually increases the duty ratio of the blower

motor control signal to prevent too much air from blowing. 

• The time period from when the air flow changes from LOW to HI is approximately 8 seconds.
• It becomes the starting air flow control at low coolant temperature according to the calculation result of auto

amp and engine coolant temperature [approximately 56

°

C (133

°

F) or less] during the automatic air flow con-

trol. 

JSIIA1547GB

JPIIA1564GB