2007 NISSAN 350Z Automatic Air Conditioner Workshop Manual

AIR CONDITIONER CONTROL
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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 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 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 door motors following the form
shown in figure below.
Start:
Initial compulsory signal 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
air mix door motor, mode door motor 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 con-
trol 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 are checked for errors. Error data are then compiled. The
error check prevents corrupted data from being used by the air mix door motor, the mode 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
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Stop Signal:
At the end of each transmission, a stop operation, in-operation, or internal malfunction message is delivered to
the unified meter and A/C amp. This completes one data transmission and control cycle.
AIR MIX DOOR CONTROL (AUTOMATIC TEMPERATURE CONTROL)
The air mix door is automatically controlled so that in-vehicle temperature is maintained at a predetermined
value by the temperature setting, ambient temperature, in-vehicle temperature and amount of sunload.
FAN SPEED CONTROL
Blower speed is automatically controlled by the temperature setting, ambient temperature, in-vehicle tempera-
ture, intake temperature, amount of sunload and air mix door position.
With FAN control dial set to AUTO, the blower motor starts to gradually increase air flow volume.
When engine coolant temperature is low, the blower motor operation is delayed to prevent cool air from flow-
ing.
INTAKE DOOR CONTROL
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.
MODE DOOR CONTROL
The mode door is automatically controlled by the temperature setting, ambient temperature, in-vehicle temper-
ature, intake temperature and amount of sunload.
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AIR CONDITIONER CONTROL
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MAGNET CLUTCH CONTROL
When A/C switch is pressed, turn fan control dial to ON or set mode control dial to D/F, D/F2 or DEF position,
unified meter and A/C amp. transmits compressor ON signal to BCM.
BCM sends compressor ON signal to ECM, via CAN communication.
ECM judges whether compressor can be turned ON, based on each sensor status (refrigerant-pressure sen-
sor 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 air conditioner relay ON to operate com-
pressor.
When sending compressor ON signal to IPDM E/R via CAN communication line, ECM simultaneously sends
compressor feedback signal to unified meter and A/C amp. via CAN communication line.
Unified meter and A/C amp., then, uses input compressor feedback signal to control air inlet.
SELF-DIAGNOSIS SYSTEM
The self-diagnosis system is built into the unified meter and A/C amp. to quickly locate the cause of malfunc-
tions.
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Description of Control SystemNJS0000L
The control system consists of input sensors, switches, unified meter and A/C amp. (microcomputer) and out-
puts. The relationship of these components is shown in the figure below:
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AIR CONDITIONER CONTROL
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Control OperationNJS0000M
MODE CONTROL DIAL
The air discharge outlets are controlled with this dial.
Mode doors are set to the defrost position with this dial. Also, intake doors are set to the outside air position.
When shifting mode control dial to D/F, D/F2 or DEF position under the following conditions, compressor is
turned ON. (A/C LED ON)

FAN: O N

A/C: OFF
TEMPERATURE CONTROL DIAL (POTENTIO TEMPERATURE CONTROL)
The set temperature is increased or decreased with this dial.
FAN CONTROL DIAL
The blower speed is automatically or manually controlled with this dial. Twenty-five speeds are available for
manual control.
Shifting fan control dial to AUTO, compressor is turned ON automatically.
REAR WINDOW DEFOGGER SWITCH
When illumination is ON, rear window is defogged.
INTAKE SWITCH

When intake switch is ON, REC LED turns ON, and air inlet is fixed to REC.

When press intake switch again, FRE LED turns ON, and air inlet is fixed to FRE.

When intake switch is pressed for approximately 1.5 seconds or longer, REC and FRE LEDs blink twice.
Then, automatic control mode is entered. Inlet status is displayed even during automatic control.

When FRE LED is turned ON, shifting mode control dial to D/F, D/F2 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, D/F2 or DEF
position)
A/C SWITCH
Compressor is ON or OFF with this switch.
(Pressing the A/C switch when the fan control dial is ON, will turn OFF the A/C switch and compressor.)
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Discharge Air FlowNJS0000N
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System DescriptionNJS0000O
SWITCHES AND THEIR CONTROL FUNCTION
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CAN Communication System DescriptionNJS0000P
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN-H line, CAN-L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only. For details, refer to LAN-48,
"CAN System Specification Chart" .