1999 NISSAN PICK-UP Repair Manual

SYSTEM DESCRIPTION
Auto amplifier controls compressor operation by ambient tem-
perature and signal from ECM.
Low temperature protection control
Auto amplifier will turn the compressor ªONº or ªOFFº as deter-
mined by a signal detected by ambient sensor.
When ambient temperatures are greater than 1ÉC, the compres-
sor turns ªONº. The compressor turns ªOFFº when ambient tem-
peratures are less than þ2ÉC.
RHA094GA
TROUBLE DIAGNOSESAUTO
Magnet Clutch (Cont'd)
HA-2069

DIAGNOSTIC PROCEDURE
SYMPTOM: Magnet clutch does not engage when A/C
switch and fan switch are ON.
CHECK POWER SUPPLY FOR COM-
PRESSOR.
Disconnect compressor harness connector.
Do approx. 12 volts exist between com-
pressor harness terminal No.
V1and body
ground?
No
cYes
Check magnet clutch coil.
NG
Replace magnet clutch.
Refer to HA-69 in D22 SER-
VICE MANUAL, Publication
No. SM8E-0D22E0E.
Disconnect A/C relay.
Note
CHECK CIRCUIT CONTINUITY
BETWEEN A/C RELAY HARNESS TER-
MINAL NO.
V5AND COMPRESSOR
HARNESS TERMINAL NO.
V1.
Continuity should exist.
If OK, check harness for short.
OK
CHECK POWER SUPPLY FOR A/C
RELAY.
Disconnect A/C relay.
Do approx. 12 volts exist between A/C
relay harness terminal Nos.
V1,V3and
body ground?
Yes
cNo
CHECK POWER SUPPLY
CIRCUIT AND 7.5A
(No.
23) FUSE AT FUSE
BLOCK.
Refer to EL section (ªWir-
ing Diagramº, ªPOWER
SUPPLY ROUTINGº).
CHECK A/C RELAY AFTER DISCON-
NECTING IT.
Refer to HA-2073.
OK
cNG
Replace A/C relay.
VA
(Go to next page.)
Note:
If the result is NG or No after checking circuit continuity, repair harness or
connector.
RHA494H
RHA096GD
RHA495H
RHA496H
.
.
.
.
.
.
TROUBLE DIAGNOSESAUTO
Magnet Clutch (Cont'd)
HA-2070

VA
Note
Check circuit continuity between A/C relay
harness terminal No.
V2and thermo
switch harness terminal No.
V2.
Continuity should exist.
If OK, check harness for short.
OK
CHECK THERMO SWITCH.
Refer to HA-2074.
OK
cNG
Replace thermo switch.
Note
Check circuit continuity between thermo
switch harness terminal No.
V1and
triple-pressure switch harness terminal
No.
V4.
Continuity should exist.
If OK, check harness for short.
OK
CHECK TRIPLE-PRESSURE SWITCH.
Refer to HA-2073.
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 harness for short.
OKReplace triple-pressure
switch.
CHECK POWER SUPPLY FOR
THERMO CONTROL AMP.
Do approx. 12 volts exist between thermo
control amp. harness terminal No.
V1and
body ground?
Yes
cNo
Check power supply circuit
and 7.5A fuse (No.
23,
located in fuse block).
(Refer to ªPOWER SUP-
PLY ROUTINGº in EL sec-
tion and Wiring Diagram.)
VB
(Go to next page.)
Note:
If the result is NG or No after checking circuit continuity, repair harness or
connector.
RHA980G
RHA981G
RHA328GA
RHA319GB
.
.
.
.
..
.
.
TROUBLE DIAGNOSESAUTO
Magnet Clutch (Cont'd)
HA-2071

VB
Do approx. 12V exist between thermo
control amp. harness terminal No.
V2and
body ground?
Yes
cNo
Replace thermo control
amp.
Note
Check circuit continuity between thermo
control amp. harness terminal No.
V2and
auto amp. harness terminal No.
V4.
Continuity should exist.
If OK, check harness for short.
OK
Replace auto amp.
Note:
If the result is NG or No after checking circuit continuity, repair harness or
connector.
RHA497H
RHA498H
.
.
.
TROUBLE DIAGNOSESAUTO
Magnet Clutch (Cont'd)
HA-2072

COMPONENT INSPECTION
A/C relay
Check continuity between terminal Nos.V3andV5.
Conditions Continuity
12V direct current supply between terminal Nos.
V1andV2Yes
No current supply No
If NG, replace relay.
Triple-pressure switch
TerminalsHigh-pressure side line
pressure
kPa (bar, kg/cm2, psi)Operation Continuity
Low-pres-
sure side
V1-V4
Increasing to
152.0 - 201.0
(1.520 - 2.010,
1.55 - 2.05, 22.0 - 29.2)ON Exists.
Decreasing to
152.0 - 201.0
(1.520 - 2.010,
1.55 - 2.05, 22.0 - 29.2)OFFDoes not
exist.
Medium-
pressure
side*
V2-V3
Increasing to
1,422 - 1,618
(14.22 - 16.18,
14.5 - 16.5, 206 - 235)ON Exists.
Decreasing to
1,128 - 1,422
(11.28 - 14.22,
11.5 - 14.5, 164 - 206)OFFDoes not
exist.
High-pres-
sure side
V1-V4
Decreasing to
2,059 - 2,256
(20.6 - 22.6,
21 - 23, 299 - 327)ON Exists.
Increasing to
2,648 - 2,844
(26.5 - 28.4,
27 - 29, 384 - 412)OFFDoes not
exist.
*: For cooling fan motor operation
Thermo control amp.
Evaporator outlet air temperature
ÉC (ÉF)Thermo amp.
operationTester
Decreasing to 0.1 - 0.9 (32 - 34) Turn OFF Approx. 12V
Increasing to 2.5 - 3.5 (37 - 38) Turn ON Approx. 0V
SEF090M
RHA364GA
RHA365GA
TROUBLE DIAGNOSESAUTO
Magnet Clutch (Cont'd)
HA-2073

Thermo switch
Water temperature
ÉC (ÉF)Terminal No.
Continuity
Å@
Over 105 (221)
V1V2No
Less than 100 (212) Yes
RHA141H
TROUBLE DIAGNOSESAUTO
Magnet Clutch (Cont'd)
HA-2074

Insufficient Cooling
TROUBLE DIAGNOSIS PROCEDURE FOR INSUFFICIENT COOLING
SYMPTOM:
lInsufficient cooling.
Inspection flow
*1: HA-2035
*2: HA-2036
*3: HA-2038
*4: HA-2055
*5: HA-2060
*6: HA-2065*7: HA-2070
*8: HA-2052
*9: Refer to HA-27, D22 Service
Manual, Publication No.
SM8E-0D22E0E.*10: HA-2039
*11: HA-2041
*12: HA-2049
SHA347F
TROUBLE DIAGNOSESAUTO
HA-2075

Insufficient Heating
TROUBLE DIAGNOSIS PROCEDURE FOR INSUFFICIENT HEATING
SYMPTOM:
lInsufficient heating.
Inspection flow
*1: HA-2041
*2: HA-2035
*3: HA-2036
*4: HA-2038*5: HA-2055
*6: HA-2060
*7: HA-2065
*8: HA-2057*9: HA-2055
*10: HA-2039
*11: HA-2049
SHA346F
TROUBLE DIAGNOSESAUTO
HA-2076