1998 NISSAN PICK-UP Repair Manual

Operational Check
The purpose of the operational check is to confirm that the sys-
tem operates properly.
CONDITIONS:
lEngine running at normal operating temperature.
PROCEDURE:
1. Check blower
a. Slide fan control lever to 1-speed.
Blower should operate on 1-speed.
b. Slide fan control lever to 2-speed and continue checking
blower speed until all speeds are checked.
c. Leave blower on 4-speed.
2. Check discharge air
a. Slide mode control lever to
position.
b. Confirm that all discharge air comes out of face vents.
c. Slide mode control lever to
position.
d. Confirm that discharge air comes out of face vents and foot
vents.
e. Slide mode control lever to
position.
f. Confirm that discharge air comes out of foot vents, with some
air from defrost vents.
g. Slide mode control lever to
position.
h. Confirm that discharge air comes out of foot vents with some
air from defrost vents.
i. Slide mode control lever to
position.
j. Confirm that all discharge air comes out of defrost vents.
3. Check recirculation
a. Slide recirculation control lever to the REC
position.
b. Listen for intake door position change (you should hear
blower sound change slightly).
RHA346G
RHA347G
RHA348G
TROUBLE DIAGNOSES
HA-18

4. Check temperature decrease
a. Slide temperature control lever to full cold.
b. Check for cold air at discharge air outlets.
5. Check temperature increase
a. Slide temperature control lever to full hot.
b. Check for hot air at discharge air outlets.
6. Check A/C switch
Move fan control lever to the desired position (1 to 4) and press
air conditioner switch to turn ON air conditioner.
Indicator light will come on when air conditioner is ON.
RHA349G
RHA350G
RHA351G
TROUBLE DIAGNOSES
Operational Check (Cont'd)
HA-19

Symptom Chart
DIAGNOSTIC TABLE
PROCEDUREPreliminary
CheckDiagnostic
ProcedureMain
Power
Supply
and
Ground
Circuit
CheckElectrical Components Inspection
REFERENCE PAGE
HA-21
HA-22
HA-23
HA-37
HA-39
HA-36
HA-43
HA-43
HA-43
HA-43
HA-44
HA-44
HA-44
HA-60
HA-45
Ð
SYMPTOM
Preliminary check 1
Preliminary check 2
Preliminary check 3
Diagnostic procedure 1
Diagnostic procedure 2
15A Fuses (No.
19
and
20 )
7.5A Fuse (No.
21 )
Blower motor
Blower resistor
A/C switch
Fan switch
Thermo control amp.
A/C relay
Triple-pressure switch
Compressor
Harness Magnet clutch
Thermal protector
A/C does not blow cold air.j jjjjjjjjjjjj
Blower motor does not rotate.
jjjjj j
Magnet clutch does not
engage when A/C switch and
fan switch are ON.
j jjjjjjjj
Noise.
Insufficient heating.jj
,: The number means checking order.
j: Checking order depends on malfunction in flow chart.
TROUBLE DIAGNOSES
HA-20

Preliminary Check
PRELIMINARY CHECK 1
A/C does not blow cold air.
DOES AIR FLOW FROM VENTS?
Condition:
lEngine running at operating tem-
perature.
lIgnition switch, A/C switch, and fan
switch are ON.
lMode control lever is in FACE posi-
tion and temperature control lever
is in full cold position.
Yes
cNo
IS BLOWER MOTOR OPERATING
NORMALLY?
Yes No
CHECK BLOWER
MOTOR OPERATION.
Go toDiagnostic Pro-
cedure 1, HA-37.
CHECK COMPRESSOR BELT TEN-
SION.
Refer to MA section (``Checking
Drive Belts'', ``ENGINE MAINTE-
NANCE'').
NG OKNG
bCHECK COMPRESSOR OPERA-
TION.
OKCHECK FOR EVAPORATOR COIL
FREEZE UP.
Remove intake unit. Check if evapo-
rator freezes.
Adjust or replace com-
pressor belt.CHECK REFRIGERATION CYCLE
PRESSURE WITH MANIFOLD
GAUGE CONNECTED.
Refer to Performance Chart, HA-26.
NG OKNG
(Freezes up.)OK
(Does not
freeze up.)
CHECK REFRIGERANT.
Connect manifold gauge then check
system pressure.
Refer to ``Performance Chart'',
HA-26.
OK NGCHECK VENTILATOR
DUCT FOR AIR
LEAKS.Go toPerformance
Test Diagnoses,
HA-24.CHECK THERMO CONTROL AMP.
OPERATION.
Refer to ``Electrical Components
Inspection'', HA-44.
CHECK FOR REFRIG-
ERANT LEAKS.CHECK WATER COCK OPERA-
TION.
Except for RHD models
Warm up engine before checking.
Refer to ``Control Linkage
Adjustment'', HA-46.
OK
cNG
Adjust or replace water cock.
Go toDiagnostic Procedure 2,
HA-39.CHECK TEMPERATURE CONTROL
CABLE.
Refer to ``Control Linkage
Adjustment'', HA-47.
OK
cNG
Adjust temperature control cable.
VISUALLY INSPECT AIR MIX DOOR.Access by removing instrument
panel.
OK
cNG
Replace air mix door.
CHECK THERMO CONTROL AMP.
OPERATION.
Refer to ``Electrical Components
Inspection'', HA-44.
.
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.
.
TROUBLE DIAGNOSES
HA-21

PRELIMINARY CHECK 2
Noise
CHECK WHERE NOISE COMES FROM.
Blower motorCompressorExpansion valveRefrigerant lineBelt
CHECK FOR
NOISE IN ALL
MODES AND
TEMPERATURE
SETTINGS.
Noise is
constant
.
Inspect the com-
pressor clutch and
pulley and idler
pulley.
OK NGReplace expan-
sion valve.
CHECK
BLOWER
MOTOR AND
FAN FOR
WEAR.
OK
.
NGReplace com-
pressor clutch
and pulley.
Refer to
HA-60 or 64.
Line is fixed
directly to body.Line is not fixed.
Replace
blower
motor or
fan.CHECK DISC-TO-
PULLEY CLEAR-
ANCE.
Refer to HA-62 or
66.
OKFix line with
rubber or vibra-
tion absorbing
material.
Fix line tightly.
CHECK
BLOWER
MOTOR FOR
FOREIGN PAR-
TICLES.
NGCHECK AND
ADJUST COM-
PRESSOR
LUBRICANT.
Refer to HA-50.OK
Remove foreign
particles from
intake unit.
Replace compres-
sor and liquid
tank.Belt vibration is
intense.Side of belt is
worn out.
Noise is
intermittent
CHECK AIR DIS-
CHARGE DUCTS
FOR OBSTRUC-
TIONS, FOREIGN
MATERIALS OR
AIR LEAKAGE.
.
NGReadjust belt
tension.
Refer to MA
section
(``Checking
Drive Belts'',
``ENGINE
MAINTE-
NANCE'').
Pulley center
does not match.
Readjust pulley
center.
Refer to HA-61 or
65.
Remove obstruc-
tions or repair air
leakage.
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TROUBLE DIAGNOSES
Preliminary Check (Cont'd)
HA-22

PRELIMINARY CHECK 3
Insufficient heating
DOES AIR FLOW FROM FOOT AREA?
Condition:
lVehicle at operating temperature.
lIgnition switch and fan switch are ON.
lMode control lever is in FOOT position and tem-
perature control lever is in full hot position.
Yes
cNoCHECK BLOWER MOTOR
OPERATION.
Go toDiagnostic Procedure
1, HA-37.
Check the following:
lEngine coolant level. Refer to MA section.
lHoses for leaks or kinks.
lRadiator cap. Refer to LC section (``ENGINE
COOLING SYSTEM'').
lAir in cooling system.
OK
cNG
Repair/replace as necessary.
CHECK WATER COCK OPERATION.
Except for RHD models
Warm up engine before checking.
Refer to ``Control Linkage Adjustment'', HA-46.
OK
cNG
Adjust or replace water cock.
CHECK TEMPERATURE CONTROL CABLE.
Refer to ``Control Linkage Adjustment'', HA-47.
OK
cNG
Adjust temperature control
cable.
VISUALLY INSPECT AIR MIX DOOR.
Access by removing instrument panel.
OK
cNG
Replace air mix door.
CHECK BY FEEL HEATER INLET AND OUTLET
HOSES.
Both hoses
coldBoth hoses
warm
CHECK THERMOSTAT
INSTALLATION.
OKCHECK HEATER HOSES FOR
PROPER INSTALLATION.OK
Replace thermostat. Refer
to LC section (``Thermostat'',
``ENGINE COOLING SYS-
TEM'').
Back flush heater core, drain and refill coolant.
Retest.
Hot inlet
Warm outletBoth hoses
warm
System OK
Replace heater
core.
.
.
.
.
.
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TROUBLE DIAGNOSES
Preliminary Check (Cont'd)
HA-23

Performance Test Diagnoses
INSUFFICIENT COOLING
INSUFFICIENT COOLING
CHECK AIR FLOW.
OK
cNG
CHECK BLOWER MOTOR OPERATION.
OK NG
CHECK COMPRESSOR OPERATION.
OK NGClogged blower inlet/Clogged
duct/Loose duct connection/
Air leakage, etc.
VA
(Go to
next
page.)
VB(Go to
next page.)
OK
CHECK HIGH AND LOW-SIDE PRESSURE. USE
PERFORMANCE CHART. Refer to HA-26.
NG
RECOVER REFRIGERANT USING RECOVERY
RECYCLING EQUIPMENT AND CHARGE
SPECIFIED AMOUNT OF REFRIGERANT.
Note
CHECK HIGH AND LOW-SIDE PRESSURE. USE
PERFORMANCE CHART. Refer to HA-26.
OK
cNG
BOTH HIGH AND LOW-
PRESSURE SIDES ARE
TOO HIGH.c
cCHECK DISCHARGE AIR TEMPERATURE. USE
PERFORMANCE CHART. Refer to HA-26.
NG OKHIGH-PRESSURE SIDE
IS TOO HIGH AND LOW-
PRESSURE SIDE IS TOO
LOW.
c
ENDHIGH-PRESSURE SIDE
IS TOO LOW AND LOW-
PRESSURE SIDE IS TOO
HIGH.c
Malfunctioning temperature control operation (air
mix door position improperly adjusted)/
Malfunctioning water cock operation (incorrect
valve closure)BOTH HIGH AND LOW-
PRESSURE SIDES ARE
TOO LOW.c
LOW-PRESSURE SIDE
SOMETIMES BECOMES
NEGATIVE.c
LOW-PRESSURE SIDE
BECOMES NEGATIVE.cNote:-correspond to those in TROUBLE DIAGNOSES FOR
ABNORMAL PRESSURE.
Refer to HA-27.
.
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.
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.
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.
.
TROUBLE DIAGNOSES
HA-24

VA
Malfunctioning blower motor fan.Malfunctioning electrical circuit.Malfunctioning blower motor internal
circuit.
Loose fan/Improper contact of fan
and case/Deformed fan.Discontinued wiring or component
circuits or poor connection/
Malfunctioning resistor, amplifier,
etc./Burned out fuse or low battery
voltage.
VB
Magnet clutch does not engage.Magnet clutch slipping.Belt slipping.
CHECK MAGNET CLUTCH.
Inspect coil circuit, disc-to-pulley
clearance.CHECK COMPRESSOR BELT AND
BELT TENSION. Refer to MA sec-
tion (``Checking Drive Belts'',
``ENGINE MAINTENANCE'').
CHECK ELECTRICAL CIRCUIT.
Inspect wiring, components circuit.cMalfunctioning internal parts of
clutch, compressor.
CHECK ACTIVATION OF SAFETY/
PROTECTION DEVICES. Inspect
devices such as pressure switch,
etc.cForeign particles on clutch frictional
surface or excessive disc clear-
ance.
cMalfunctioning electrical circuit
(poor connection, low battery
voltage, etc.).
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TROUBLE DIAGNOSES
Performance Test Diagnoses (Cont'd)
HA-25