IDX INFINITI QX4 2001 Factory Service Manual

4 CHECK FOR AUTO AMP. OUTPUT
Set up Self-diagnosis STEP 4.
Measure voltage across auto amp. harness terminals and body ground.
RHA823H
MTBL0468
OK or NG
OK©Replace intake door motor.
NG©Replace auto amp.
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TROUBLE DIAGNOSES
Intake Door Motor (Cont'd)
HA-93

Blower Motor
TROUBLE DIAGNOSIS PROCEDURE FOR BLOWER MOTOR=NBHA0094SYMPTOM:
IBlower motor operation is malfunctioning.
IBlower motor operation is malfunctioning under out of starting fan speed control.
Inspection FlowNBHA0094S01Without Navigation SystemNBHA0094S0101
SHA248FA
*1: HA-44
*2: HA-129
*3: HA-132
*4: HA-135
*5: HA-141*6: STEP-BY-STEP PROCEDURE
(HA-45), see No. 13.
*7: HA-98
*8: HA-98
*9: HA-45*10: HA-66
*11: HA-65
*12: HA-66
*13: HA-139
*14: EL-108
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TROUBLE DIAGNOSES
Blower Motor
HA-95

SYSTEM DESCRIPTION=NBHA0062Component partsNBHA0062S01Fan speed control system components are:
1) Auto amp.
2) Fan control amp.
3) A/C LAN system (PBR built-in mode door motor and air mix door motor)
4) In-vehicle sensor
5) Ambient sensor
6) Sunload sensor
7) Intake sensor
System OperationNBHA0062S02
SHA006FF
Automatic ModeNBHA0062S03In the automatic mode, the blower motor speed is calculated by the automatic amplifier based on inputs from
the PBR, in-vehicle sensor, sunload sensor, intake sensor and ambient sensor. The blower motor applied
voltage ranges from approximately 5 volts (lowest speed) to 12 volts (highest speed).
The control blower speed (in the range of 5 to 12V), the automatic amplifier supplies a gate voltage to the fan
control amplifier. Based on this voltage, the fan control amplifier controls the voltage supplied to the blower
motor.
Starting Fan Speed ControlNBHA0062S04Start Up From ªCOLD SOAKº Condition (Automatic mode)NBHA0062S0401In a cold start up condition where the engine coolant temperature is below 50ÉC (122ÉF), the blower will not
operate for a short period of time (up to 126 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 126 seconds as described above.
After this delay, the blower will operate at low speed until the engine coolant temperature rises above 55ÉC
(131ÉF), at which time the blower speed will increase to the objective speed.
Start Up From Normal or ªHOT SOAKº Condition (Automatic mode)
NBHA0062S0402The blower will begin operation momentarily after the AUTO button is pushed. 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).
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TROUBLE DIAGNOSES
Blower Motor (Cont'd)
HA-97

1 CHECK POWER SUPPLY FOR FAN CONTROL AMP.
Disconnect fan control amp. harness connector.
Do approx. 12 volts exist between fan control amp. harness terminal No. 3 and body ground?
RHA480G
YesorNo
Ye s©GO TO 2.
No©GO TO 8.
2 CHECK BODY GROUND CIRCUIT FOR FAN CONTROL AMP.
Does continuity exist between fan control amp. harness terminal No. 1 and body ground?
RHA089G
YesorNo
Ye s©Reconnect fan control amp. harness connector. And GO TO 3.
No©Repair harness or connector.
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TROUBLE DIAGNOSES
Blower Motor (Cont'd)
HA-99

6 CHECK FAN FEED BACK CIRCUIT
Reconnect auto amp. (LCU) harness connector.
Do approx. 12 volts exist between auto amp. (LCU) harness terminal No. 33 and body ground?
RHA825H
YesorNo
Ye s©GO TO 7.
No©Check power supply circuit and 15A fuses (Nos. 1 and 2, located in the fuse block).
Refer to EL-14, ªWiring Diagram Ð POWER к.
IIf OK, check for open circuit in wiring harness.
Repair or replace as necessary.
IIf NG, replace fuse and check wiring harness for short circuit.
Repair or replace as necessary.
7 CHECK POWER SUPPLY FOR AUTO AMP.
Do approx. 12 volts exist between auto amp. harness terminal No. 34 and body ground?
RHA826H
YesorNo
Ye s©1. Replace auto amp.
2. Go to self-diagnosis step-by-step procedure (HA-45) and perform self-diagnosis STEP
4.
Confirm that blower motor operation is normal.
No©GO TO 10.
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TROUBLE DIAGNOSES
Blower Motor (Cont'd)
HA-101

10 CHECK BLOWER MOTOR CIRCUIT BETWEEN BLOWER MOTOR AND AUTO AMP. (LCU)
Check circuit continuity between blower motor harness terminal No. 2 and auto amp. (LCU) harness terminal No. 34.
RHA827H
Continuity should exist.
If OK, check harness for short.
OK or NG
OK©INSPECTION END
NG©Repair harness or connector.
RHA941F
COMPONENT INSPECTIONNBHA0065Blower MotorNBHA0065S01Confirm smooth rotation of the blower motor.
IEnsure that there are no foreign particles inside the intake unit.
RHA828H
Fan Control AmplifierNBHA0065S02Check continuity between terminal Nos. 1 and 2.
Terminal No. Continuity
1-2 Yes
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TROUBLE DIAGNOSES
Blower Motor (Cont'd)
HA-103

With Navigation SystemNBHA0095S0102
RHA876H
*1: STEP-BY-STEP PROCEDURE
(HA-44)
*2: HA-129
*3: HA-132
*4: HA-135
*5: HA-141*6: STEP-BY-STEP PROCEDURE
(HA-45), see No. 13.
*7: HA-106
*8: HA-150
*9: HA-155
*10: HA-66*11: HA-45
*12: HA-66
*13: HA-65
*14: HA-139
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TROUBLE DIAGNOSES
Magnet Clutch (Cont'd)
HA-105

2 CHECK CIRCUIT CONTINUITY BETWEEN A/C RELAY AND COMPRESSOR
Check circuit continuity between A/C relay harness terminal No. 5 and compressor harness terminal No. 1.
RHA748FB
Continuity should exist.
If OK, check harness for short.
OK or NG
OK©GO TO 3.
NG©Repair harness or connector.
3 CHECK POWER SUPPLY FOR A/C RELAY
Disconnect A/C relay.
Do approx. 12 volts exist between A/C relay harness terminal Nos. 2, 3 and body ground?
RHA614F
YesorNo
Ye s©GO TO 4.
No©Check power supply circuit and 7.5A (No. 6) fuse at fuse block.
Refer to EL-14, ªWiring Diagram Ð POWER к.
IIf OK, check for open circuit in wiring harness.
Repair or replace as necessary.
IIf NG, replace fuse and check wiring harness for short circuit.
Repair or replace as necessary.
4 CHECK A/C RELAY AFTER DISCONNECTING IT
Refer to HA-110.
OK or NG
OK©Reconnect A/C relay. And GO TO 5.
NG©1. Replace A/C relay.
2. Go to self-diagnosis step-by-step procedure (HA-45) and perform self-diagnosis STEP
4.
Confirm that magnet clutch operation is normal.
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TROUBLE DIAGNOSES
Magnet Clutch (Cont'd)
HA-107

7 CHECK CIRCUIT CONTINUITY BETWEEN ECM AND AUTO AMP.
Check circuit continuity between ECM harness terminal No. 45 and auto amp. harness terminal No. 22.
RHA878H
Continuity should exist.
If OK, check harness for short.
OK or NG
OK©GO TO 8.
NG©1. Repair harness or connector.
2. Go to ªSTEP-BY-STEP PROCEDUREº, ªSelf-diagnosisº, HA-45 and perform self-diag-
nosis STEP 4.
Confirm that magnet clutch operation is normal.
8 CHECK REFRIGERANT PRESSURE SENSOR
Refer to EC-641, ªDiagnostic Procedureº, HA-111.
OK or NG
OK©GO TO 9.
NG©Replace refrigerant pressure sensor.
9 CHECK VOLTAGE FOR ECM
Check 4.6 volts exist between ECM harness terminal No. 51 and body ground?
RHA482GG
YesorNo
Ye s©Check ECM. Refer to EC-127, ªECM Terminal and Reference Valueº.
No©GO TO 10.
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TROUBLE DIAGNOSES
Magnet Clutch (Cont'd)
HA-109

RHA880H
SHA315F
Refrigerant Pressure SensorNBHA0068S02Make sure that higher A/C refrigerant pressure results in higher
refrigerant-pressure sensor output voltage.
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TROUBLE DIAGNOSES
Magnet Clutch (Cont'd)
HA-111