1998 NISSAN PICK-UP Repair Manual

HHA134
.
HAþA/C, Mþ02
TROUBLE DIAGNOSES
Wiring Diagram Ð A/C Ð (Cont'd)
HA-34

HHA135
.
HAþA/C, Mþ03.To
HAþA/C, M
þ01
TROUBLE DIAGNOSES
Wiring Diagram Ð A/C Ð (Cont'd)
HA-35

Main Power Supply and Ground Circuit
Check
POWER SUPPLY FUSE CHECK FOR A/C SYSTEM
Check the following fuses.
l15A fuse (No.19 and20 ) for blower motor.
l7.5A fuse (No.21 ) for thermo control amp.
For detailed circuit, refer to ``Wiring Diagram''.
THERMO CONTROL AMP. CHECK
Power supply circuit check
Check power supply circuit for thermo control amp. with ignition
switch ON.
1. Disconnect thermo control amp. harness connector.
2. Connect voltmeter from harness side.
3. Measure voltage across terminal No.
V1and body ground.
Voltmeter terminal
Voltage
Å@
V1Body ground Approx. 12V
Ground circuit check
Check body ground circuit for thermo control amp. with ignition
switch ON, air conditioner switch ON and fan switch ON.
1. Disconnect thermo control amp. harness connector.
2. Connect ohmmeter from harness side.
3. Check for continuity between terminal No.
V2and body
ground.
Ohmmeter terminal
Continuity
Å@
V2Body ground Yes
If the ground circuit is NG, check the following.
lA/C switch (Refer to HA-43.)
lFan switch (Refer to HA-43.)
lHarness for open or short between thermo control amp. and
A/C switch
lHarness for open or short between A/C switch and fan switch
lFan switch ground circuit
SHA877E
RHA319GA
SHA102F
TROUBLE DIAGNOSES
HA-36

INCIDENTFlow chart
No.
1 Fan fails to rotate.
2 Fan does not rotate at 1-speed.
3 Fan does not rotate at 2-speed.
4 Fan does not rotate at 3-speed.
5 Fan does not rotate at 4-speed.
Diagnostic Procedure 1
SYMPTOM: Blower motor does not rotate.
lPerform PRELIMINARY CHECK 1 before referring to the
following flow chart.
Check if blower motor rotates properly
at each fan speed.
Conduct checks as per flow chart at
left.
cVE
cVD
cVC
cVB
(Go to next page.)
CHECK POWER SUPPLY FOR BLOWER
MOTOR.
Disconnect blower motor harness connec-
tor.
Do approx. 12 volts exist between blower
motor harness terminal No.
V1and body
ground?
Yes
cNo
Check 15A fuses (No.19
and No.20 , located in
the fuse block).
(Refer to ``POWER SUP-
PLY ROUTING'' in EL sec-
tion and Wiring Diagram.)
1. Turn fan control knob to any position
except OFF.
2. Check circuit continuity between blower
motor harness terminal No.
V2and
body ground.
Continuity should exist.
OK
cNG
Reconnect blower motor
harness connector.
CHECK BLOWER MOTOR.
(Refer to Electrical Components Inspec-
tion.) (HA-43)
NG
Replace blower motor.
.
CHECK BLOWER MOTOR CIRCUIT
BETWEEN BLOWER MOTOR AND
RESISTOR.
Do approx. 12 volts exist between resistor
harness terminal No.
V1and body
ground?
Yes
cNo
Disconnect blower motor
and resistor harness con-
nectors.
Disconnect fan switch harness connector.Note
Check circuit continuity
between blower motor har-
ness terminal No.
V2and
resistor harness terminal
No.
V1.
Continuity should exist.
If OK, check harness for
short.
VA(Go to next page.)
Note:
If the result is NG after checking circuit continuity, repair harness or con-
nector.
SHA872E
SHA873E
RHA320G
RHA321G
.
.
.
.
..
.
TROUBLE DIAGNOSES
HA-37

VA
Note
CHECK GROUND CIRCUIT FOR FAN
SWITCH.
Check circuit continuity between fan switch
harness terminal No.
V26and body ground.
OK
CHECK BLOWER RESISTOR AFTER DIS-
CONNECTING IT.
(Refer to Electrical Components Inspection.)
(HA-43)
OK NG
bVB
bVC
bVD
Replace resistor.VE
Reconnect resistor harness connector.
...
CHECK FAN SWITCH CIRCUIT.
Do approx. 12 volts exist between each fan switch har-
ness terminal and body ground?
Yes No
.
Note
Check circuit continuity
between fan switch harness
terminal and resistor har-
ness terminal.
If OK, check harness for
short.
CHECK FAN SWITCH AFTER DIS-
CONNECTING IT.
(Refer to Electrical Components
Inspection.) (HA-43)cNG
Replace fan switch.
Note:
If the result is NG after checking circuit continuity, repair harness or con-
nector.
Flow chart
No.Terminal No.
Voltage
Å@
V24
Body ground Approx. 12VV23
V22
V21
Terminal No.
Conti-
nuity Fan
switchResistor
V21V1
YesV22V2
V23V3
V24V4
SHA097F
SHA098F
SHA099F
.
.
.
.
.
.
.
TROUBLE DIAGNOSES
Diagnostic Procedure 1 (Cont'd)
HA-38

Diagnostic Procedure 2
EXCEPT FOR KA ENGINE MODELS
SYMPTOM: Magnet clutch does not engage when A/C
switch and fan switch are ON.
lPerform PRELIMINARY CHECK 1 before referring to the
following flow chart.
CHECK POWER SUPPLY FOR COM-
PRESSOR.
Disconnect compressor harness connec-
tor.
Do approx. 12 volts exist between com-
pressor harness terminal No.
V1and body
ground?
No
cYes
Check the following.
lMagnet clutch coillThermal protector (Except
for the Middle East)
NG
Replace magnet clutch.
Refer to HA-60.
Note
Check circuit continuity between A/C relay
harness terminal No.
V5and compressor
harness terminal No.
V1.
Continuity should exist.
If OK, check harness for short.
OK
CHECK POWER SUPPLY FOR A/C
RELAY.
Do approx. 12 volts exist between A/C
relay harness terminal No.
V3and body
ground?
Yes
cNo
Check power supply circuit
and 7.5A fuse (No.
21 ,
located in the fuse block).
(Refer to ``POWER SUP-
PLY ROUTING'' in EL sec-
tion and Wiring Diagram.)
CHECK POWER SUPPLY FOR A/C
RELAY.
Do approx. 12 volts exist between A/C
relay harness terminal No.
V1and body
ground?
No
cYes
Check power supply circuit
and 7.5A fuse (No.
21 ,
located in the fuse block).
(Refer to ``POWER SUP-
PLY ROUTING'' in EL sec-
tion and Wiring Diagram.)
CHECK A/C RELAY AFTER DISCON-
NECTING IT.
Refer to HA-44.
OK
cNG
Replace A/C relay.
Reconnect A/C relay.
Note
Check circuit continuity between A/C relay
harness terminal No.
V2and triple-pres-
sure switch harness terminal No.
V4.
Continuity should exist.
If OK, check harness for short.
OK
VA(Go to next page.)
Note:
If the result is NG after checking circuit continuity, repair harness or con-
nector.
RHA325G
RHA748FD
RHA359G
RHA375G
RHA327GA
.
.
.
.
.
.
.
.
TROUBLE DIAGNOSES
HA-39

VA
CHECK TRIPLE-PRESSURE SWITCH.
Refer to HA-44.
OK
cNG
Check refrigerant charge
amount.
OK
Note
Check circuit continuity between triple-
pressure switch harness terminal No.
V1
and thermo control amp. harness terminal
No.
V3.
Continuity should exist. If OK, check har-
ness for short.
OKReplace triple-pressure
switch.
CHECK POWER SUPPLY AND GROUND
CIRCUIT FOR THERMO CONTROL AMP.
Refer to HA-36.
OK
Replace thermo control amp.
Note:
If the result is NG after checking circuit continuity, repair harness or con-
nector.
SHA100F
.
..
.
.
TROUBLE DIAGNOSES
Diagnostic Procedure 2 (Cont'd)
HA-40

FOR KA ENGINE MODELS
SYMPTOM: Magnet clutch does not engage when A/C
switch and fan switch are ON.
lPerform PRELIMINARY CHECK 1 before referring to the
following flow chart.
CHECK POWER SUPPLY FOR COM-
PRESSOR.
Disconnect compressor harness connec-
tor.
Do approx. 12 volts exist between com-
pressor harness terminal No.
V1and body
ground?
No
cYes
Check the following.
lMagnet clutch coil
lThermal protector
NG
Replace magnet clutch.
Refer to HA-60.
Note
Check circuit continuity between A/C relay
harness terminal No.
V5and compressor
harness terminal No.
V1.
Continuity should exist.
If OK, check harness for short.
OK
CHECK POWER SUPPLY FOR A/C
RELAY.
Do approx. 12 volts exist between A/C
relay harness terminal No.
V3and body
ground?
Yes
cNo
Check power supply circuit
and 7.5A fuse (No.
21 ,
located in the fuse block).
(Refer to ``POWER SUP-
PLY ROUTING'' in EL sec-
tion and Wiring Diagram.)
CHECK POWER SUPPLY FOR A/C
RELAY.
Do approx. 12 volts exist between A/C
relay harness terminal No.
V1and body
ground?
Yes
cNo
Check power supply circuit
and 7.5A fuse (No.
21 ,
located in the fuse block).
(Refer to ``POWER SUP-
PLY ROUTING'' in EL sec-
tion and Wiring Diagram.)
CHECK A/C RELAY AFTER DISCON-
NECTING IT.
Refer to HA-44.
OK
cNG
Replace A/C relay.
Reconnect A/C relay.
VA
(Go to next page.)
Note:
If the result is NG after checking circuit continuity, repair harness or con-
nector.
RHA333G
RHA334G
RHA359G
RHA375G
.
.
.
.
.
.
.
TROUBLE DIAGNOSES
Diagnostic Procedure 2 (Cont'd)
HA-41