1998 NISSAN PATROL sensor

jA
STEP 2 - SENSOR CIRCUITS ARE
CHECKED FOR OPEN OR SHORT
CIRCUIT.
Does code No.
appear on the dis-
play?
Ye sNo
.
Turn temperature
dial clockwise.Refer to the following chart for malfunctioning code
No.
(If two or more sensors malfunction, corresponding
code Nos. blink respectively two times.)
*1: Conduct self-diagnosis STEP 2 under sunshine.
When conducting indoors, aim a light (more than
60W) at sunload sensor, otherwise Code No.
will indicate despite that sunload sensor is func-
tioning properly. j
B
(Go to next page.)
Code No.Malfunctioning sensor
(including circuits)Reference
page
Ambient sensor HA-103A/C LED
In-vehicle sensor HA-105A/C LED
Sunload sensor*1 HA-107A/C LED
Air mix door motor
(LCU) PBRHA-79
A/C LED
RHA970DA
RHA528G
RHA501A
.
.
.
TROUBLE DIAGNOSESAUTO
Self-diagnosis (Cont'd)
HA-65

A/C System
TROUBLE DIAGNOSIS PROCEDURE FOR A/C SYSTEM
SYMPTOM:
+A/C system does not come on.
Inspection ¯ow
*1: HA-74 *2: HA-70
COMPONENT DESCRIPTION
Automatic ampli®er (Auto amp.)
The auto ampli®er has a built-in microcomputer which processes
information sent from various sensors needed for air conditioner
operation. The air mix door motor, mode door motor, intake door
motor, blower motor and compressor are then controlled.
The auto ampli®er is unitized with control mechanisms. Signals
from various switches and Potentio Temperature Control (PTC) are
directly entered into auto ampli®er.
Self-diagnostic functions are also built into auto ampli®er to provide
quick check of malfunctions in the auto air conditioner system.
Potentio temperature control (PTC)
The PTC is built into the A/C auto amp. It can be set at an interval
of 1ÉC in the 18ÉC to 32ÉC temperature range by turning the tem-
perature dial. The set temperature is digitally displayed.
SHA019F
RHA629G
RHA746G
TROUBLE DIAGNOSESAUTO
HA-73

SYSTEM DESCRIPTION
Component parts
Mode door control system components are:
1) Auto amp.
2) Mode door motor (LCU)
3) In-vehicle sensor
4) Ambient sensor
5) Sunload sensor
6) Intake sensor
System operation
The auto ampli®er receives data from each of the sensors. The ampli®er sends air mix door and mode door
opening angle data to the air mix door motor LCU and mode door motor LCU.
The air mix door motor and mode door motor read their respective signals according to the address signal.
Opening angle indication signals received from the auto ampli®er and each of the motor position sensors are
compared by the LCUs in each motor with the existing decision and opening angles. Subsequently, HOT/
COLD or DEFROST/VENT operation is selected. The new selection data is returned to the auto ampli®er.
SHA006FA
TROUBLE DIAGNOSESAUTO
Mode Door Motor (Cont'd)
HA-76

SYSTEM DESCRIPTION
Component parts
Air mix door control system components are:
1) Auto amp.
2) Air mix door motor (LCU)
3) In-vehicle sensor
4) Ambient sensor
5) Sunload sensor
6) Intake sensor
System operation
The auto ampli®er receives data from each of the sensors. The ampli®er sends air mix door and mode door
opening angle data to the air mix door motor LCU and mode door motor LCU.
The air mix door motor and mode door motor read their respective signals according to the address signal.
Opening angle indication signals received from the auto ampli®er and each of the motor position sensors are
compared by the LCUs in each motor with the existing decision and opening angles. Subsequently, HOT/
COLD or DEFROST/VENT operation is selected. The new selection data is returned to the auto ampli®er.
RHA424GB
TROUBLE DIAGNOSESAUTO
Air Mix Door Motor (Cont'd)
HA-80

SYSTEM DESCRIPTION
Component parts
Intake door control system components are:
1) Auto amp.
2) Intake door motor
3) A/C LAN system (PBR built-in mode motor and air mix door motor)
4) In-vehicle sensor
5) Ambient sensor
6) Sunload sensor
7) Intake sensor
System operation
The intake door control determines intake door position based on the ambient temperature, the intake air
temperature and the in-vehicle temperature. When the A/C, DEFROSTER, or OFF switches are pushed, the
auto ampli®er sets the intake door at the ``Fresh'' position.
RHA640G
TROUBLE DIAGNOSESAUTO
Intake Door Motor (Cont'd)
HA-83

SYSTEM DESCRIPTION
Component parts
Fan speed control system components are:
1) Auto amp.
2) Fan control amp.
3) A/C LAN system (PBR built in mode door motor and air mix door motor)
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 ampli®er 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 ampli®er supplies a gate voltage to the fan
control ampli®er. Based on this voltage, the fan control ampli®er controls the voltage supplied to the blower
motor.
Starting fan speed control
Start up from ``COLD SOAK'' condition (Automatic mode)
In a cold start up condition where the engine coolant temperature is below 50ÉC, the blower will not operate
for a short period of time (up to 150 seconds). The exact start delay time varies depending on the ambient
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 ``HOT SOAK'' 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 objective
blower speed).
SHA006FB
TROUBLE DIAGNOSESAUTO
Blower Motor (Cont'd)
HA-87

SYSTEM DESCRIPTION
Auto ampli®er controls compressor operation by ambient tempera-
ture and signal from ECM (ECCS control module).
Low temperature protection control
Auto ampli®er will turn the compressor ``ON'' or ``OFF'' as deter-
mined by a signal detected by ambient sensor.
When ambient temperatures are greater than 1ÉC, the compressor
turns ``ON''. The compressor turns ``OFF'' when ambient tempera-
tures are less than þ2ÉC.
RHA094GA
TROUBLE DIAGNOSESAUTO
Magnet Clutch (Cont'd)
HA-93

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