2004 INFINITI FX35 ground

ATC-30
AIR CONDITIONER CONTROL
Revision: 2004 November 2004 FX35/FX45
AIR CONDITIONER CONTROLPFP:27500
Description of Air Conditioner LAN Control SystemAJS0014A
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 diagram below.
System ConstructionAJS0014B
A small network is constructed between the unified meter and A/C amp., air mix door motor, mode 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 the 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 air mix door motor, mode door motor and 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 are compared by the LCUs in each motor with the existing decision and opening
angles. Subsequently, HOT/COLD, DEFROST/VENT or FRESH/RECIRCULATION operation is selected. The
new selection data is returned to the unified meter and A/C amp.
SJIA0262E
RJIA1747E

ATC-42
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
How to Perform Trouble Diagnosis for Quick and Accurate RepairAJS0014K
WORK FLOW
SYMPTOM TABLE
*1ATC-61, "Operational Check"
SHA900E
Symptom Reference Page
A/C system does not come on. Go to Trouble Diagnosis Procedure for A/C System.AT C - 6 3 , "
Power
Supply and Ground
Circuit for Auto
Amp."
A/C system cannot be controlled.
Go to Integrated Display System.

Go to Navigation System.AV-78, "
Trouble
Diagnosis Chart by
Symptom" (Without
navigation system)
or AV-84, "
A/C and
AV Switch Does Not
Operate" (With nav-
igation system)
Air outlet does not change.
Go to Trouble Diagnosis Procedure for Mode Door Motor. (LAN)AT C - 7 0 , "
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)ATC-73, "
Air Mix
Door Motor Circuit"Air mix door motor does not operate nor-
mally.
Intake door does not change.
Go to Trouble Diagnosis Procedure for Intake Door Motor. (LAN)ATC-76, "
Intake
Door Motor Circuit"Intake door motor does not operate nor-
mally.
Blower motor operation is malfunctioning.
Go to Trouble Diagnosis Procedure for Blower Motor.ATC-79, "
Blower
Motor Circuit"Blower motor operation is malfunctioning
under out of starting fan speed control.
Magnet clutch does not engage. Go to Trouble Diagnosis Procedure for Magnet Clutch.ATC-84, "
Magnet
Clutch Circuit"
Insufficient coolingGo to Trouble Diagnosis Procedure for Insufficient Cooling.AT C - 9 1 , "
Insufficient
Cooling"
Go to Diagnostic Procedure for Insufficient Cooling.AT C - 9 8 , "
DIAG-
NOSTIC PROCE-
DURE FOR
INSUFFICIENT
COOLING"
Insufficient heating Go to Trouble Diagnosis Procedure for Insufficient Heating.ATC-100, "Insuffi-
cient Heating"
Noise Go to Trouble Diagnosis Procedure for Noise.ATC-101, "Noise"
Self-diagnosis cannot be performed. Go to Trouble Diagnosis Procedure for Self-diagnosis.ATC-102, "Self-
diagnosis"
Memory function does not operate. Go to Trouble Diagnosis Procedure for Memory Function.ATC-103, "Memory
Function"

TROUBLE DIAGNOSIS
ATC-51
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AT C
Revision: 2004 November 2004 FX35/FX45
Auto Amp. Terminals and Reference ValueAJS0014O
Measure voltage between each terminal and ground by following ter-
minals and reference value for unified meter and A/C amp.
PIN CONNECTOR TERMINAL LAYOUT
TERMINALS AND REFERENCE VALUE FOR UNIFIED METER AND A/C AMP.
RJIA1965E
RJIA1966E
Terminal
No.Wire
colorItemIgnition
switchConditionVoltage
(V)
1 L CAN H - - -
11 R C A N L - - -
21 R/W Power supply for BATT OFF - Battery voltage
22 G/R Power supply for IGN ON - Battery voltage
29 B Ground (Power) ON - Approx. 0
30 B Ground ON - Approx. 0
35 LG/R Power supply for ACC ON - Battery voltage
39 Y Ambient sensor - - -
40 BR/W In-vehicle sensor - - -
41 P Intake sensor - - -
42 R/Y Compressor ON signal ONA/C switch: ON Approx. 0
A/C switch: OFF Approx. 5
43 G/B A/C LAN signal ON -
45 PU/WECV (Electric Control Valve)
signalON -
HAK0652D
RJIA1606E

ATC-52
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
46 L/W Power supply for IGN2 ON - Battery voltage
49 W/G Sensor ground ON - Approx. 0
50 LG Sunload sensor - - -
53 G Blower motor control signal ON Blower speed: 1st step
54 Y/RPower supply for each door
motorON - Battery voltage
57 BR/Y Blower motor ON signal ONA/C switch: ON (Blower motor
operate)Approx. 0
A/C switch: OFF Approx. 5 Te r m i n a l
No.Wire
colorItemIgnition
switchConditionVoltag e
(V)
SJIA0116J

TROUBLE DIAGNOSIS
ATC-63
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AT C
Revision: 2004 November 2004 FX35/FX45
CHECKING AUTO MODE
1. Press AUTO switch and A/C switch.
2. Display should indicate AUTO.

Confirm that the compressor clutch engages (sound or visual
inspection). (Discharge air and blower speed will depend on
ambient, in-vehicle, and set temperatures.)
If NG, go to trouble diagnosis procedure for AT C - 6 3 , "
Power Supply
and Ground Circuit for Auto Amp." , then if necessary, trouble diag-
nosis procedure for AT C - 8 4 , "
Magnet Clutch Circuit" .
If all operational checks are OK (symptom cannot be duplicated), go
to malfunction Simulation Tests in GI-27, "
How to Perform Efficient
Diagnosis for an Electrical Incident" and perform tests as outlined to
simulate driving conditions environment. If symptom appears, refer
to AT C - 4 2 , "
SYMPTOM TABLE" and perform applicable trouble diagnosis procedures.
Power Supply and Ground Circuit for Auto Amp.AJS001BF
SYMPTOM: A/C system does not come on.
INSPECTION FLOW
RJIA1979E
*1AT C - 6 4 , "DIAGNOSTIC PROCE-
DURE FOR A/C SYSTEM".*2ATC-61, "
Operational Check".*3AV- 7 8 , "Trouble Diagnosis Chart by
Symptom".
*4AV- 8 4 , "
A/C and AV Switch Does Not
Operate".
RJIA1980E

TROUBLE DIAGNOSIS
ATC-65
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AT C
Revision: 2004 November 2004 FX35/FX45
1. CHECK POWER SUPPLY CIRCUIT FOR UNIFIED METER AND A/C AMP.
1. Disconnect unified meter and A/C amp. connector.
2. Check voltage between unified meter and A/C amp. harness
connector M56 terminals 21 (R/W), 22 (G/R) and 35 (LG/R), uni-
fied meter and A/C amp. harness connector M57 terminal 46 (L/
W) and ground.
OK or NG
OK >> GO TO 2.
NG >> Check 10A and 15A fuses [Nos. 6, 10, 11, 12 and 19, located in the fuse block (J/B)]. Refer to PG-
83, "FUSE BLOCK - JUNCTION BOX (J/B)" .

If fuses are OK, check harness for open circuit. Repair or replace if necessary.

If fuses are NG, replace fuse and check harness for short circuit. Repair or replace if necessary.
2. CHECK GROUND CIRCUIT FOR UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Check continuity between unified meter and A/C amp. harness
connector M56 terminal 29 (B), 30 (B) and ground.
OK or NG
OK >> Replace unified meter and A/C amp.
NG >> Repair harness or connector.
Terminals Ignition switch position
(+)
(-) OFF ACC ON Unified
meter and
A/C amp.
connectorTerminal No.
(wire color)
M56 21 (R/W)
GroundBattery
voltageBattery
voltageBattery
voltage
M56 22 (G/R) Approx. 0V Approx. 0VBattery
voltage
M56 35 (LG/R) Approx. 0VBattery
voltageBattery
voltage
M57 46 (L/W) Approx. 0VBattery
voltageBattery
voltage
RJIA1984E
29, 30 – Ground : Continuity should exist.
RJIA1985E

ATC-66
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
LAN System CircuitAJS0014S
SYMPTOM: Mode door motor, intake door motor and/or air mix door motor(s) does not operate normally.
DIAGNOSTIC PROCEDURE FOR LAN CIRCUIT
1. CHECK POWER SUPPLY FOR UNIFIED METER AND A/C AMP.
1. Turn ignition switch ON.
2. Check voltage between unified meter and A/C amp. harness
connector M57 terminal 54 (Y/R) and ground.
OK or NG
OK >> GO TO 2.
NG >> Replace unified meter and A/C amp.
2. CHECK SIGNAL FOR UNIFIED METER AND A/C AMP.
Confirm A/C LAN signal between unified meter and A/C amp. har-
ness connector M57 terminal 43 (G/B) and ground using an oscillo-
scope.
OK or NG
OK >> GO TO 3.
NG >> Replace unified meter and A/C amp.
RJIA1775E
54 – Ground : Battery voltage
RJIA1986E
Terminals
Voltage (+)
(−)
Unified meter and A/
C amp. connectorTerminal No.
(wire color)
M57 43 (G/B) Ground
RJIA1987E
HAK0652D

TROUBLE DIAGNOSIS
ATC-67
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AT C
Revision: 2004 November 2004 FX35/FX45
3. CHECK POWER SUPPLY FOR MOTOR
Check voltage between mode door motor harness connector M258
terminal 1 (G), driver side air mix door motor harness connector
M252 terminal 1 (G), passenger side air mix door motor harness
connector M257 terminal 1 (G), intake door motor harness connector
M253 terminal 1 (G) and ground.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4. CHECK SIGNAL FOR MOTOR
Confirm A/C LAN signal between mode door motor harness connec-
tor M258 terminal 3 (L), driver side air mix door motor harness con-
nector M252 terminal 3 (L), passenger side air mix door motor
harness connector M257 terminal 3 (L), intake door motor harness
connector M253 terminal 3 (G/B) and ground using an oscilloscope.
OK or NG
OK >> GO TO 5.
NG >> Repair harness or connector.
5. CHECK MOTOR GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect door motor connector.
3. Check continuity between mode door motor harness connector
M258 terminal 2 (B), driver side air mix door motor harness con-
nector M252 terminal 2 (B), passenger side air mix door motor
harness connector M257 terminal 2 (B), intake door motor har-
ness connector M253 terminal 2 (B) and ground.
OK or NG
OK >> GO TO 6.
NG >> Repair harness or connector.1 – Ground : Battery voltage
RJIA1988E
Door motorTerminals
Voltage (+)
(−)
Con-
nectorTerminal
No.
(wire color)
Mode M258 3 (L)
Ground Air mix
(Driver
side)M252 3 (L)
Air mix
(Passen-
ger side)M257 3 (L)
Intake M253 3 (L)
RJIA1989E
HAK0652D
2 – Ground : Continuity should exist.
RJIA1990E