1998 NISSAN PATROL Heather And Air Conditioner Workshop Manual

Ambient Sensor
COMPONENT DESCRIPTION
The ambient sensor is attached in front of the driver's side con-
denser. It detects ambient temperature and converts it into a resis-
tance value which is then input into the auto ampli®er.
AMBIENT TEMPERATURE INPUT PROCESS
The automatic ampli®er includes a ``processing circuit'' for the ambi-
ent sensor input. However, when the temperature detected by the
ambient sensor increases quickly, the processing circuit retards the
auto amp. function. It only allows the auto amp. to recognize an
ambient temperature increase of 0.33ÉC per 100 seconds.
As an example, consider stopping for a cup of coffee after high
speed driving. Although the actual ambient temperature has not
changed, the temperature detected by the ambient sensor will
increase. This is because the heat from the engine compartment
can radiate to the front grille area, location of the ambient sensor.
RHA670G
TROUBLE DIAGNOSESAUTO
HA-103

DIAGNOSTIC PROCEDURE
SYMPTOM: Ambient sensor circuit is open or shorted. (orA/C LEDis indicated on auto amp. as a result of conducting
Self-diagnosis STEP 2.)
CHECK AMBIENT SENSOR CIRCUIT
BETWEEN AMBIENT SENSOR AND
AUTO AMP.
Disconnect ambient sensor harness con-
nector.
Do approx. 5 volts exist between ambient
sensor harness terminal No.j
9and body
ground?
Ye s
cNo
Disconnect auto amp. har-
ness connector.
Note
Check circuit continuity
between ambient sensor
harness terminal No.j
9
and auto amp. harness
terminal No.j
9.
OK
Disconnect auto amp. harness connector.
Replace auto amp.
Note
Check circuit continuity between ambient
sensor harness terminal No.j
24and auto
amp. harness terminal No.j
24.
OK
CHECK AMBIENT SENSOR.
(Refer to HA-105.)
OK
cNG
Replace ambient sensor.
Replace auto amp.
Note:
If the result is NG or No after checking circuit continuity, repair harness
or connector.
RHA051GC
RHA671G
RHA672G
RHA673G
.
..
.
.
.
TROUBLE DIAGNOSESAUTO
Ambient Sensor (Cont'd)
HA-104

COMPONENT INSPECTION
Ambient sensor
After disconnecting ambient sensor harness connector, measure
resistance between terminalsj
9andj24at sensor harness side,
using the table below.
Temperature ÉC (ÉF) Resistance kW
þ15 (5) 12.73
þ10 (14) 9.92
þ5 (23) 7.80
0 (32) 6.19
5 (41) 4.95
10 (50) 3.99
15 (59) 3.24
20 (68) 2.65
25 (77) 2.19
30 (86) 1.81
35 (95) 1.51
40 (104) 1.27
45 (113) 1.07
In-vehicle Sensor
COMPONENT DESCRIPTION
In-vehicle sensor
The in-vehicle sensor is located on instrument lower panel. It con-
verts variations in temperature of compartment air drawn from the
aspirator into a resistance value. It is then input into the auto ampli-
®er.
Aspirator
The aspirator is located in front of heater unit. It produces vacuum
pressure due to air discharged from the heater unit, continuously
taking compartment air in the aspirator.
RHA674G
RHA675G
RHA636F
RHA482A
TROUBLE DIAGNOSESAUTO
Ambient Sensor (Cont'd)
HA-105

DIAGNOSTIC PROCEDURE
SYMPTOM: In-vehicle sensor circuit is open or shorted.
(
orA/C LEDis indicated on auto amp. as a result of con-
ducting Self-diagnosis STEP 2.)
CHECK IN-VEHICLE SENSOR CIRCUIT
BETWEEN IN-VEHICLE SENSOR AND
AUTO AMP.
Disconnect in-vehicle sensor harness con-
nector.
Do approx. 5 volts exist between in-ve-
hicle sensor harness terminal No.j
8and
body ground?
Ye s
cNo
Disconnect auto amp. har-
ness connector.
Note
Check circuit continuity
between in-vehicle sensor
harness terminal No.j
8
and auto amp. harness
terminal No.j
8.
OK
Disconnect auto amp. harness connector.
Replace auto amp.
Note
Check circuit continuity between in-vehicle
sensor harness terminal No.j
24and auto
amp. harness terminal No.j
24.
OK
CHECK IN-VEHICLE SENSOR.
(Refer to HA-107.)
OK
cNG
Replace in-vehicle sensor.
Replace auto amp.
Note:
If the result is NG or No after checking circuit continuity, repair harness
or connector.
RHA056GE
RHA676G
RHA677G
RHA678G
.
..
.
.
.
TROUBLE DIAGNOSESAUTO
In-vehicle Sensor (Cont'd)
HA-106

COMPONENT INSPECTION
In-vehicle sensor
After disconnecting in-vehicle sensor harness connector, measure
resistance between terminalsj
8andj24at sensor harness side,
using the table below.
Temperature ÉC (ÉF) Resistance kW
þ15 (5) 12.73
þ10 (14) 9.92
þ5 (23) 7.80
0 (32) 6.19
5 (41) 4.95
10 (50) 3.99
15 (59) 3.24
20 (68) 2.65
25 (77) 2.19
30 (86) 1.81
35 (95) 1.51
40 (104) 1.27
45 (113) 1.07
Sunload Sensor
COMPONENT DESCRIPTION
The sunload sensor is located on the right defroster grille. It detects
sunload entering through windshield by means of a photo diode.
The sensor converts the sunload into a current value which is then
input into the auto ampli®er.
SUNLOAD INPUT PROCESS
The auto amp. also includes a processing circuit which ``average''
the variations in detected sunload over a period of time. This pre-
vents drastic swings in the ATC system operation due to small or
quick variations in detected sunload.
For example, consider driving along a road bordered by an occa-
sional group of large trees. The sunload detected by the sunload
sensor will vary whenever the trees obstruct the sunlight. The pro-
cessing circuit averages the detected sunload over a period of time,
so that the (insigni®cant) effect of the trees momentarily obstruct-
ing the sunlight does not cause any change in the ATC system
operation. On the other hand, shortly after entering a long tunnel,
the system will recognize the change in sunload, and the system
will react accordingly.
RHA679G
RHA682G
TROUBLE DIAGNOSESAUTO
In-vehicle Sensor (Cont'd)
HA-107

DIAGNOSTIC PROCEDURE
SYMPTOM: Sunload sensor circuit is open or shorted. (orA/C LEDis indicated on auto amp. as a result of conducting
Self-diagnosis STEP 2.)
CHECK SUNLOAD SENSOR CIRCUIT
BETWEEN SUNLOAD SENSOR AND
AUTO AMP.
Disconnect sunload sensor harness con-
nector.
Do approx. 5 volts exist between sunload
sensor harness terminal No.j
10and body
ground?
Ye s
cNo
Disconnect auto amp. har-
ness connector.
Note
Check circuit continuity
between sunload sensor
harness terminal No.j
10
and auto amp. harness
terminal No.j
10.
OK
Disconnect auto amp. harness connector.
Replace auto amp.
Note
Check circuit continuity between sunload
sensor harness terminal No.j
24and auto
amp. harness terminal No.j
24.
OK
CHECK SUNLOAD SENSOR.
(Refer to HA-109.)
OK
cNG
Replace sunload sensor.
Replace auto amp.
Note:
If the result is NG or No after checking circuit continuity, repair harness
or connector.
RHA061GC
RHA680G
RHA681G
RHA683G
.
..
.
.
.
TROUBLE DIAGNOSESAUTO
Sunload Sensor (Cont'd)
HA-108

COMPONENT INSPECTION
Sunload sensor
Measure voltage between auto amp. terminalj10and body ground.
+When checking sunload sensor, select a place where sun
shines directly on it.
RHA684G
SHA930E
TROUBLE DIAGNOSESAUTO
Sunload Sensor (Cont'd)
HA-109

Intake Sensor
COMPONENT DESCRIPTION
The intake sensor is located on the cooling unit. It converts tem-
perature of air after it passes through the evaporator into a resis-
tance value. The value is then input to the auto ampli®er.
DIAGNOSTIC PROCEDURE
SYMPTOM: Intake sensor circuit is open or shorted.
CHECK INTAKE SENSOR CIRCUIT
BETWEEN INTAKE SENSOR AND AUTO
AMP.
Disconnect intake sensor harness connec-
tor.
Do approx. 5 volts exist between intake
sensor harness terminal No.j
25and body
ground?
Ye s
cNo
Disconnect auto amp. har-
ness connector.
Note
Check circuit continuity
between intake sensor har-
ness terminal No.j
25and
auto amp. harness terminal
No.j
25.
Continuity should exist.
If OK, check harness for
short.
OK
Disconnect auto amp. harness connector.
Replace auto amp.
Note
Check circuit continuity between intake
sensor harness terminal No.j
24and auto
amp. harness terminal No.j24.
Continuity should exist.
If OK, check harness for short.
OK
CHECK INTAKE SENSOR.
(Refer to HA-111.)
OK
cNG
Replace intake sensor.
Replace auto amp.
Note:
If the result is NG or No after checking circuit continuity, repair harness
or connector.
RHA685G
RHA957FA
RHA686G
RHA687G
RHA688G
.
..
.
.
.
TROUBLE DIAGNOSESAUTO
HA-110