2008 INFINITI FX35 air condition

AIR CONDITIONER CONTROLATC-27
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Description of Control SystemINFOID:0000000001328169
The control system consists of input sensors, swit ches, the unified meter and A/C amp. (microcomputer) and
outputs. The relationship of these co mponents is shown in the figure below:
Control OperationINFOID:0000000001328170
DISPLAY SCREEN
The operation status of the system is displayed on the screen.
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 mainta ined at the set temperature selected by the operator.
SJIA1658E
SJIA1567E
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ATC-28
< SERVICE INFORMATION >
AIR CONDITIONER CONTROL
 When pressing AUTO switch, air inlet, air outlet, fan speed, and discharge air temperature are automatically
controlled.
TEMPERATURE CONTROL SWITCH (POTENTIO TEMPERATURE CONTROL) (DRIVER SIDE)
The set temperature is increased or decreased with this switch.
TEMPERATURE CONTROL SWITCH (POTENTIO TEMPERATURE CONTROL) (PASSENGER
SIDE)
 The set temperature is increased or decreased with this switch.
 When the temperature switch is pressed, the DUA L switch indicator will automatically illuminate.
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, 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)
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.
REAR WINDOW DEFOGGER SWITCH
When illumination is ON, rear window is defogged.
OFF SWITCH
Compressor and blower are OFF, the intake door s and the mode doors are automatically controlled.
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.)
MODE SWITCH
The air discharge outlets is controlled with this switch.
FAN SWITCH
The blower speed is manually controlled with this swit ch. Seven speeds are available for manual control (as
shown on the display screen).
DUAL SWITCH
 When the DUAL switch indicator is illuminated, the driver side and passenger side temperature can each be set independently.
 When the DUAL switch indicator is not illuminated, t he driver side setting temperature is applied to both
sides.
Fail-Safe FunctionINFOID:0000000001328171
If a communication error exists between the unified meter and A/C amp., and the A/C and AV switch for 30
seconds or longer, air conditioner is controlled under following conditions:
Compressor : ON
Air outlet : AUTO
Air inlet : FRE (Fresh)
Blower fan speed : AUTO
Set temperature : Setting befo re communication error occurs
Display : OFF
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AIR CONDITIONER CONTROLATC-29
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Discharge Air FlowINFOID:0000000001328172
SJIA1568E
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ATC-30
< SERVICE INFORMATION >
AIR CONDITIONER CONTROL
System Description
INFOID:0000000001328173
SWITCHES AND THEIR CONTROL FUNCTION
CAN Communication System DescriptionINFOID:0000000001328174
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 s peed and excellent error detection ability. Many elec-
SJIA1610E
SJIA1890E
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AIR CONDITIONER CONTROLATC-31
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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-43,
"CAN System Specification Chart".
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ATC-32
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
TROUBLE DIAGNOSIS
CONSULT-III FunctionINFOID:0000000001328175
CONSULT-III can display each diagnosis item using the diagnosis test modes shown following.
DATA MONITOR
Display Item List
How to Perform Trouble Diagnosis for Quick and Accurate RepairINFOID:0000000001328176
WORK FLOW
SYMPTOM TABLE
System part Check item, diagnosis mode Description
BCM Data monitor Displays BCM input data in real time.
Monitor item name “operation or unit” Contents
IGN ON SW “On/Off” Displays “IGN position (On)/OFF, ACC position (Off)” status as judged from ignition switch signal.
FAN ON SIG “On/Off” Displays “FAN (On)/FAN (Off)” status as judged from blower fan motor switch signal.
AIR COND SW “On/Off” Di splays “COMP (On)/COMP (Off)” status as judged from air conditioner switch signal.
*1AT C - 5 0 , "Operational Check"
SHA900E
Symptom Reference Page
A/C system does not come on. Go to Trouble Diagnosis Procedure for A/C System. AT C - 5 2 , "
Power
Supply and Ground
Circuit for Auto
Amp"
A/C system cannot be controlled.
 Go to Integrated Display System.
 Go to Navigation System. AV- 7 9 , "
Unable to
Operate System
with A/C and AV
Switch" (Without
navigation system)
or AV- 1 2 7 , "
Unable
to Operate System
with A/C and AV
Switch" (With navi-
gation system)
Air outlet does not change. Go to Trouble Diagnosis Procedure for Mode Door Motor. (LAN) AT C - 5 7 , "
Mode
Door Motor Circuit"Mode door motor does not operate normally.
Discharge air temperature does not change.
Go to Trouble Diagnosis Procedure for Air Mix Door Motor. (LAN) AT C - 5 9 , "
Air Mix
Door Motor Circuit"Air mix door motor does not operate normal-
ly.
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ATC-52
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
If all operational checks are OK (symptom cannot be duplicated), go to Incident Simulation Tests in GI-25,
"How to Perform Efficient Diagnosis for an Electrical Incident" and perform tests as outlined to simulate driving
conditions environment. If symptom appears, refer to ATC-32, "
How to Perform Trouble Diagnosis for Quick
and Accurate Repair" and perform applicable trouble diagnosis procedures.
Power Supply and Ground Circuit for Auto AmpINFOID:0000000001328183
SYMPTOM: A/C system does not activate.
INSPECTION FLOW
COMPONENT DESCRIPTION
Unified Meter and A/C Amp. (Automatic Amplifier)
The unified meter and A/C amp. has a built-in microcomputer which
processes information sent from various sensors needed for air con-
ditioner operation. The air mix door motor, mode door motor, intake
door motor, blower motor and compressor are then controlled.
When the various switches and temperature control switch are oper-
ated, data is input to the unified meter and A/C amp. from the display
control unit using CAN communication.
Self-diagnosis functions are also built into unified meter and A/C
amp. to provide quick check of malfunctions in the auto air condi-
tioner system.
Potentio Temperature Control (PTC)
*1 "DIAGNOSIS PROCEDURE FOR A/
C SYSTEM" *2
AT C - 5 0 , "Operational Check"*3AV- 7 9 , "Unable to Operate System
with A/C and AV Switch" (Without
navigation system) or AV- 1 2 7 , "
Un-
able to Operate System with A/C and
AV S w i t c h" (With navigation system)
SJIA1582E
SJIA1566E
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ATC-66
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
 Intake sensor
System Operation
Automatic Mode
In the automatic mode, the blower motor speed is calculated by the unified meter and A/C amp. based on the
input from the PBR, in-vehicle sensor, sunl oad sensor, intake sensor and ambient sensor.
When the air flow is increased, the duty ratio of the blower fan motor’s drive signal is changed at 8%/sec. to
prevent a sudden increase in air flow.
In addition to manual air flow control and the usual automat ic air flow control, starting air flow control, low
water temperature starting control and high passenger co mpartment temperature starting control are avail-
able.
Starting Fan Speed Control
Start up from COLD SOAK Condition (Automatic mode)
In a cold start up condition where the engine coolant temperature is below 56 °C (133 °F), the blower will not
operate for a short period of time (up to 150 seconds ). The exact start delay time varies depending on the
ambient and engine coolant temperature.
In the most extreme case (very low ambient) the blower starting delay will be 150 seconds as described
above. After this delay, the blower will operate at lo w speed until the engine coolant temperature rises above
56 °C (133 °F), and then the blower speed will increase to the objective speed.
Start up from usual or HOT SOAK Condition (Automatic mode)
The blower will begin operation momentarily after the AU TO switch is pressed. The blower speed will gradu-
ally rise to the objective speed over a time period of 3 seconds or less (actual time depends on the objective
blower speed).
Blower Speed Compensation
Sunload
When the in-vehicle temperature and the set temperature are very close, the blower will be operating at low
speed. The low speed will vary depending on the sunload. Du ring conditions of low or no sunload, the blower
speed is at duty ratio 25%. During high sunload conditi ons, the unified meter and A/C amp. raise the blower
speed (duty ratio 49%).
Fan Speed Control Specification
RJIA1995E
RJIA1996E
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