Ac system INFINITI QX4 2001 Factory Service Manual

A/C System
TROUBLE DIAGNOSIS PROCEDURE FOR A/C SYSTEM=NBHA0089SYMPTOM:
IA/C system does not come on.
INSPECTION FLOW
RHA866H
*1: HA-72 *2: HA-66 *3: HA-142
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
A/C System
HA-71

RHA464GA
RHA858H
MAIN POWER SUPPLY AND GROUND CIRCUIT CHECKNBHA0037Component DescriptionNBHA0037S01Automatic Amplifier (Auto Amp.)NBHA0037S0101The auto amplifier has a built-in microcomputer which processes
information sent from various sensors needed for air conditioner
operation. The air mix door motor, mode door motor, intake door
motor, blower motor and compressor are then controlled.
The auto amplifier is unitized with control mechanisms. Signals
from various switches and Potentio Temperature Control (PTC) are
directly entered into auto amplifier.
Self-diagnostic functions are also built into auto amplifier to provide
quick check of malfunctions in the auto air conditioner system.
RHA464GA
RHA867H
Potentio Temperature Control (PTC)NBHA0037S0102The PTC is built into the A/C auto amp. or Display & NAVI control
unit. It can be set at an interval of 0.5ÉC (1.0ÉF) in the 18ÉC (65ÉF)
to 32ÉC (85ÉF) temperature range by pushing the temperature but-
ton. The set temperature is digitally displayed.
TROUBLE DIAGNOSES
A/C System (Cont'd)
HA-72

RHA817H
DIAGNOSTIC PROCEDURENBHA0107SYMPTOM:
IA/C system does not come on.
RHA818H
Auto Amp. CheckNBHA0107S01Check power supply circuit for auto amp. with ignition switch ON.
Measure voltage across terminal Nos. 26, 27, 33 (24, 25, 33) and
body ground.
Voltmeter terminal
Voltage
(+) (þ)
26 (24)
Body ground Approx. 12V 27 (25)
33 (33)
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
A/C System (Cont'd)
HA-73

SHA967EE
RHA868H
Check body ground circuit for auto amp. with ignition switch OFF.
Check for continuity between terminal Nos. 32, 14 and body
ground.
Ohmmeter terminal
Continuity
(+) (þ)
32
Body ground Yes
14 (Canada only)
If OK, check auto amp. ground circuit, see below.
IIf NG, check 7.5A fuses (Nos. 11 and 24, located in the fuse
block) and 15A fuses (Nos. 1 and 2, located in the fuse block).
IIf fuses are OK, check for open circuit in wiring harness.
Repair or replace as necessary.
IIf fuses are NG, replace fuse and check wiring harness for
short circuit. Repair or replace as necessary.
NOTE:
If OK, replace auto amp.
If NG, repair or replace harness.
TROUBLE DIAGNOSES
A/C System (Cont'd)
HA-74

Mode Door Motor
TROUBLE DIAGNOSIS PROCEDURE FOR MODE DOOR MOTOR (LAN)=NBHA0090SYMPTOM:
IAir outlet does not change.
IMode door motor does not operate normally.
Inspection FlowNBHA0090S01Without Navigation SystemNBHA0090S0101
SHA245F
*1: HA-25
*2: HA-66
*3: HA-44
*4: HA-45
*5: HA-129*6: HA-132
*7: HA-135
*8: HA-141
*9: STEP-BY-STEP PROCEDURE
(HA-45), see No. 13.*10: HA-78
*11: HA-81
*12: HA-66
*13: HA-65
*14: HA-139
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
Mode Door Motor
HA-75

With Navigation SystemNBHA0090S0102
RHA869H
*1: HA-25
*2: HA-66
*3: HA-44
*4: HA-45
*5: HA-129*6: HA-132
*7: HA-135
*8: HA-141
*9: STEP-BY-STEP PROCEDURE
(HA-45), see No. 13.*10: HA-78
*11: HA-81
*12: HA-66
*13: HA-65
*14: HA-139
TROUBLE DIAGNOSES
Mode Door Motor (Cont'd)
HA-76

SYSTEM DESCRIPTION=NBHA0052Component PartsNBHA0052S01Mode door control system components are:
1) Auto amp.
2) Mode door motor (LCU)
3) In-vehicle sensor
4) Ambient sensor
5) Sunload sensor
6) Intake sensor
System OperationNBHA0052S02The auto amplifier receives data from each of the sensors. The amplifier sends air mix door and mode door
opening angle data to the air mix door motor LCU and mode door motor LCU.
The air mix door motor and mode door motor read their respective signals according to the address signal.
Opening angle indication signals received from the auto amplifier 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 or DEFROST/VENT operation is selected. The new selection data is returned to the auto amplifier.
RHA870H
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
Mode Door Motor (Cont'd)
HA-77

Air Mix Door Motor
TROUBLE DIAGNOSIS PROCEDURE FOR AIR MIX DOOR (LAN)=NBHA0098SYMPTOM:
IDischarge air temperature does not change.
IAir mix door motor does not operate.
Inspection FlowNBHA0098S01Without Navigation SystemNBHA0098S0101
SHA246F
*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-78
*8: HA-85
*9: HA-85*10: HA-66
*12: HA-66
*13: HA-65
*14: HA-139
*15: HA-45
TROUBLE DIAGNOSES
Air Mix Door Motor
HA-82

With Navigation SystemNBHA0098S0102
RHA871H
*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-78
*8: HA-85
*9: HA-85*10: HA-66
*12: HA-66
*13: HA-65
*14: HA-139
*15: HA-45
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
Air Mix Door Motor (Cont'd)
HA-83

SYSTEM DESCRIPTION=NBHA0059Component PartsNBHA0059S01Air mix door control system components are:
1) Auto amp.
2) Air mix door motor (LCU)
3) In-vehicle sensor
4) Ambient sensor
5) Sunload sensor
6) Intake sensor
System OperationNBHA0059S02The auto amplifier receives data from each of the sensors. The amplifier sends air mix door and mode door
opening angle data to the air mix door motor LCU and mode door motor LCU.
The air mix door motor and mode door motor read their respective signals according to the address signal.
Opening angle indication signals received from the auto amplifier 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 or DEFROST/VENT operation is selected. The new selection data is returned to the auto amplifier.
RHA872H
TROUBLE DIAGNOSES
Air Mix Door Motor (Cont'd)
HA-84