NISSAN PICK-UP 1999 Repair Manual

CONTROL LINKAGE ADJUSTMENT
Intake door
1. Install intake door motor on intake unit and connect it to main
harness.
2. Set up code No.
in Self-diagnosis STEP 4. Refer to
HA-2038.
3. Move intake door link by hand and hold it in REC position.
4. Clamp intake door control cable. Refer to HA-54 in D22 Ser-
vice Manual, Publication No. SM8E-0D22E0E.
5. Make sure intake door operates properly when changing
from code No.
toby pushing DEF switch.
REC 20% FRE FRE
RHA485H
TROUBLE DIAGNOSESAUTO
Intake Door Motor (Cont'd)
HA-2061

Blower Motor
TROUBLE DIAGNOSIS PROCEDURE FOR BLOWER MOTOR
SYMPTOM:
lBlower motor operation is malfunctioning.
lBlower motor operation is malfunctioning under out of starting fan speed control.
Inspection flow
*1: HA-2035
*2: HA-2036
*3: HA-2038
*4: HA-2065*5: HA-2081
*6: HA-2083
*7: HA-2085
*8: HA-2087*9: HA-2055
*10: HA-2041
*11: HA-2040
SHA340F
TROUBLE DIAGNOSESAUTO
HA-2062

SYSTEM DESCRIPTION
Component parts
Fan speed control system components are:
1) Auto amp.
2) Fan control amp.
3) PBR
4) In-vehicle sensor
5) Ambient sensor
6) Sunload sensor
7) Intake sensor
System operation
Automatic mode
In 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 control
Start up from ªCOLD SOAKº condition (Automatic mode)
In a cold start up condition where the engine coolant temperature is below 50ÉC, the blower will not oper-
ate for a short period of time (up to 150 seconds). The exact start delay time varies depending on the ambi-
ent and engine coolant temperature.
In the most extreme case (very low ambient) the blower starting delay will be 150 seconds as described
above. After this delay, the blower will operate at low speed until the engine coolant temperature rises above
55ÉC, at which time the blower speed will increase to the objective speed.
Start up from normal or ªHOT SOAKº condition (Automatic mode)
The 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 objec-
tive blower speed).
SHA006FC
TROUBLE DIAGNOSESAUTO
Blower Motor (Cont'd)
HA-2063

Blower speed compensation
Sunload
When the in-vehicle temperature and the set temperature are very close, the blower will be operating at low
speed. The low speed will vary depending on the sunload. During conditions of high sunload, the blower
low speed is ªnormalº low speed (approx. 6V). During low or no sunload conditions, the low speed will drop
to ªlowº low speed (approx. 5V).
Ambient
When the ambient temperature is in the ªmoderateº range [10 - 15ÉC], the computed blower voltage will be
compensated (reduced) by up to 3.5V (depending on the blower speed). In the ªextremeº ambient ranges
[below 0ÉC and above 20ÉC] the computed objective blower voltage is not compensated at all. In the ambi-
ent temperature ranges between ªmoderateº and ªextremeº [0 - 10ÉC and 15 - 20ÉC], the amount of com-
pensation (for a given blower speed) varies depending on the ambient temperature.
Fan speed control specification
COMPONENT DESCRIPTION
Fan control amplifier
The fan control amplifier is located on the cooling unit. The fan
control amp. receives a gate voltage from the auto amp. to step-
lessly maintain the blower fan motor voltage in the 5 to 12 volt
range (approx.).
RHA389H
RHA488H
TROUBLE DIAGNOSESAUTO
Blower Motor (Cont'd)
HA-2064

DIAGNOSTIC PROCEDURE
SYMPTOM: Blower motor operation is malfunctioning under
Starting Fan Speed Control.
CHECK POWER SUPPLY FOR FAN
CONTROL AMP.
Disconnect fan control amp. harness con-
nector.
Do approx. 12 volts exist between fan
control amp. harness terminal No.
V3and
body ground?
Yes
cNo
CHECK POWER SUPPLY
FOR BLOWER MOTOR.
Disconnect blower motor
harness connector.
Do approx. 12 volts exist
between blower motor har-
ness terminal No.
V1and
body ground?
No
.
Yes
Note
CHECK BODY GROUND CIRCUIT FOR
FAN CONTROL AMP.
Does continuity exist between fan control
amp. harness terminal No.
V1and body
ground?
YesCheck
power sup-
ply circuit
and 15A
fuses (No.21and22,
located in
the fuse
block).
Note
Reconnect fan control amp. harness con-
nector.
Check circuit continuity
between blower motor har-
ness terminal No.
V2and
fan control amp. harness
terminal No.
V3.
OK
CHECK FOR AUTO AMP. OUTPUT.
Set up Self-diagnosis STEP 4.
Measure voltage across fan control amp.
harness terminal No.
V2and body
ground.
OKCHECK BLOWER
MOTOR.
(Refer to HA-2067.)
NG
Replace blower motor.
cNGVA(Go to next page.)
Replace fan control amp.
Note:If the result is NG or No after checking circuit continuity, repair harness or
connector.
Code No.Terminal No.
VoltageÅ@
þ
V2Body groundApprox.
2.5-3VApprox.
9 - 10V
RHA087GB
RHA489H
RHA490H
RHA645GA
RHA523H
..
.
..
.
.
TROUBLE DIAGNOSESAUTO
Blower Motor (Cont'd)
HA-2065

VA
Disconnect auto amp. and fan control
amp. harness connector.
Note
Does continuity exist between auto amp.
harness terminal No.
V17and fan control
amp. harness terminal No.
V2?
Continuity should exist.
If OK, check harness for short.
Yes
CHECK FAN FEED BACK CIRCUIT.
Do approx. 12 volts exist between auto
amp. harness terminal No.
V20and body
ground?
Yes
cNo
Check power supply circuit
and 15A fuses (No.
21
and22, located in the fuse
block).
Refer to EL section (ªWir-
ing Diagramº, ªPOWER
SUPPLY ROUTINGº).
Note
Do approx. 12 volts exist between auto
amp. harness terminal No.
V18and body
ground?
Yes
cNo
Check circuit continuity
between blower motor har-
ness terminal No.
V2and
auto amp. harness terminal
No.
V18.
Continuity should exist.
If OK, check harness for
short.
Replace auto amp.
Note:
If the result is NG or No after checking circuit continuity, repair harness
or connector.
RHA491H
RHA648GA
RHA649GA
RHA650GA
RHA492H
.
.
.
.
.
TROUBLE DIAGNOSESAUTO
Blower Motor (Cont'd)
HA-2066

COMPONENT INSPECTION
Blower motor
Confirm smooth rotation of the blower motor.
lEnsure that there are no foreign particles inside the intake
unit.
RHA493H
TROUBLE DIAGNOSESAUTO
Blower Motor (Cont'd)
HA-2067

Magnet Clutch
TROUBLE DIAGNOSIS PROCEDURE FOR MAGNET CLUTCH
SYMPTOM:
lMagnet clutch does not engage.
Inspection flow
*1: HA-2035
*2: HA-2036
*3: HA-2038
*4: HA-2070
*5: HA-2081*6: HA-2083
*7: HA-2085
*8: HA-2087
*9: HA-2055
*10: HA-2041*11: HA-2040
*12: HA-28 in D22 Service
Manual, Publication No.
SM8E-0D22E0E
SHA341F
TROUBLE DIAGNOSESAUTO
HA-2068

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