1998 ISUZU TROOPER sensor

1BÐ78 AIR CONDITIONING
107 13
65 12
14
1115
2 1
3
9 8
4
852RY00003
Legend
(1) Liquid Line (High-Pressure Pipe)
(2) Pressure Switch
(3) Receiver Drier
(4) Ambient Sensor
(5) Compressor Bracket
(6) Discharge Line (High-Pressure Hose)
(7) Suction Line (Low-Pressure Hose)(8) Compressor
(9) Condenser Assembly
(10) O-ring
(11) Insulator Pipe
(12) Suction Line (Low-Pressure Pipe)
(13) Drain Hose
(14) Evaporator Assembly
(15) A/C Switch
4JX1 (RHD)

AIR CONDITIONING 1BÐ79
852RY00004
107
65
12
2 1
3
9 8
11
4
Legend
(1) Liquid Line (High-Pressure Pipe)
(2) Pressure Switch
(3) Receiver Drier
(4) Ambient Sensor
(5) Compressor Bracket
(6) Discharge Line (High-Pressure Hose)(7) Suction Line (Low-Pressure Hose)
(8) Compressor
(9) Condenser Assembly
(10) Drain Hose
(11) Evaporator Assembly
(12) A/C Switch
4JX1 (LHD)

1BÐ84 AIR CONDITIONING
OVERVIEW OF CONSTRUCTION,
MOVEMENT AND CONTROL OF MAJOR
PARTS OF FULL AUTOMATIC AIR
CONDITIONER SYSTEM
Automatic Heater/Air Conditioner Control Unit
Equipped with the built-in micro-computer, this
control unit operates on signals from sensors and
input signals from switches to offer total control of
the blower fan, and actuators used for the mode
door, intake door and air mix door.
Its self-diagnosis function enables quicker access to
a failed part and its more accurate troubleshooting.
In Car Sensor
It is a sensor used for detecting room temperature
of a vehicle. This sensor converts a given room
temperature into a resistance value before entering
the data to the automatic heater/air conditioner
control unit.
This in car sensor unites the power driven aspirator
and the motor fan so that a small amount of room
air may be constantly fed to the sensor.
This sensor is provided on the control panel.
Legend
(1) In Car Sensor
(2) Full Automatic Air Conditioner Control UnitAmbient Sensor
This sensor is used for detecting temperature
outside the vehicle. It converts a given outside air
temperature into a resistance value before entering
the data to the automatic heater/air conditioner
control unit.
Thermal effects from the condenser and radiator
during idling after a run can be measured and offset
the automatic amplifier.
This sensor is provided on the side plate situated at
upper right side of the condenser.
Legend
(1) Ambient Sensor
(2) Condenser Assembly
¥ Duct Sensor
The sensor is the sensor to detect temperature
change of the side of evaporator blower coming
by fresh recirculation of intake door or "on" "off"
of compressor.
The temperature is converted to resistant rate.
And it works as thermostat to control to prevent
freezing of evaporator.
This sensor is installed in the upper case of
evaporator.


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865RY00006
21
845RY00001

AIR CONDITIONING 1BÐ85
Legend
(1) Duct Sensor
(2) Evaporator Assembly
(3) Amplifierblock
In Car Sensor
It is a photodiode used for detecting quantity of
solar radiation. This sensor converts the offset
signal generated by changes in the interior
temperature (which results from fluctuations in
solar radiation) into photoelectric current to enter
into the automatic heater/air conditioner control
unit.
This sensor is provided at top of the defroster grill.
Legend
(1) Sun SensorActuator
The actuators are power driven type containing a
small motor. Receiving output current from the
automatic heater/air conditioner control unit,
actuators drive the heater and blower unit mode
doors.
Actuators consist of the mode actuator used for
switching the mode (blow port selection), the mix
actuator used for changing aperture of the air mix
door, the intake actuator used for switching the
intake mode(fresh air/interior air).
Legend
(1) Mix Actuator
(2) Heater Unit
(3) Mode Actuator
(4) Blower Unit
(5) Intake Actuator
The actuator changes the motor speed using the
gear and drives each door rotating the output axis
united with the sliding contact.
2 31
860RX013
1
826RY00001
This illustration is based on RHD
2
5
431
860RX012
This illustration is based on RHD

1BÐ88 AIR CONDITIONING
OVERVIEW OF AUTOMATIC CONTROL OF
FULL AUTOMATIC AIR CONDITIONER
The full automatic heater and air conditioner on this
vehicle has the following features:
¥ Interior temperature control.
¥ Air flow control.
¥ Mode (blow port) control.
¥ Intake (switching between fresh air and interior
air) control.
¥ Heater start timing control.
¥ Cooler start timing control.
¥ Evaporator anti-freeze control.
1. Interior Temperature Control
The automatic heater/air conditioner control unit
operates on the setup temperature signal from
the temperature control switch and other sensor
signals to derive the total signal. Then, the
control unit compares this signal against the
signal from the potentiometer to determine
rotation direction of the mix actuator. The mix
actuator moves the air mix door to the aperture
specified by the total signal so that the specified
interior temperature is achieved.
If the compressor is turned off in the A/C (air
conditioning) mode, aperture of the air mix door
is offset according to the outside air temperature
or the specified interior temperature. This
function removes the difference in the blowing
temperature in this state and that of when the
compressor is turned on.
When FH or FC is selected for the setup
temperature, the air mix door is accordingly
fixed to the Full Heat or Full Cool mode.
When the VENT mode is selected, aperture of
the air mix door is controlled so that excessively
heated air may not be blown from the VENT
blow port.
0 50
140 104 68 32
Air mix door aperture
Full cool
Heater
side Restriction on the
aperture enabied
in the VENT modeAir conditioning
ON mode Full heatSet temperature
signal
Mix
actuator
Potentio
meter
Air mix door
In car sensor
Ambient sensor
Sun sensor
Control unitAir conditioning
switch
Set up temperature
signal
Air conditioning
OFF mode
Total signal Cooler
side
C01RY00011

AIR CONDITIONING 1BÐ89
2. Air Flow Control
¥ In the Auto Mode
The automatic heater/air conditioner control unit
operates on the setup temperature signal and
other sensor signals to derive the total signal.
Then, the control unit adjusts base potential of
the power transistor to match it to the voltage
pattern of the target fan so that stage-less fan
speed control can be achieved.
When solar radiation quantity is detected in the
VENT or B/L mode, the control unit increases the
minimum fan voltage to offset.
When FH or FC is selected from the temperature
control switch, air flow is accordingly fixed to
MAX HI or AUTO HI.
¥ In the Manual Mode
Air flow specified from the fan switch is entered
to the automatic heater/air conditioner control
unit as the manual signal. The signal modifies
the air flow to the level specified from the fan
switch so that the required fan voltage is
attained.3. Mode (Blow Port) Control
The automatic heater/air conditioner control unit
operates on the setup temperature from the
control switch, and temperature and solar
radiation quantify from the sensors to determine
the total mode control signal. According to the
pattern specified by this signal, the control unit
selects either one of the VENT, BI-LEVEL, FOOT
or DEF/FOOT mode.
The mode actuator determines the rotation
direction comparing the target position against
the current position being determined by the
position detection signal.
When FH or FC is selected for the temperature
from the temperature control switch, mode is
accordingly fixed to the VENT or FOOT.
¥ In the manual operation of the mode switch, you
can select a desired blow port mode pressing
the corresponding mode switch.
¥ Operating the DEF mode switch selects the DEF
for the blow port mode.
4.512
(V)
M
MAX
HI Relay
Power
transistor
4.8 10.5MAX HI Set up
temperature signal
Control unit
In car sensor
Ambient sensor
Sun sensor
Mode control
signal Fan switch
AUTO HI
Heater
sideCooler
side Total signalVENT mode
Blower fan motor terminal voltage
C01RY00008
Mode control
DEF / FOOTSet up temperature
signal
Mode actuator
Mode doorPosition
detection
switch
Control unit
In car sensor
Sun sensor
Air conditioning
switch
Mode control
signal Ambient sensor
FOOT
BI-LEVEL
VENT
Heater
sideCooler
side Mode total signal
C01RY00009

1BÐ90 AIR CONDITIONING
4. Intake (Fresh air/interior air switching) Control
In the Full Auto mode, the automatic heater/air
conditioner control unit operates on the setup
temperature signal and other sensor input
signals to derive the total signal. According to
the pattern specified by this signal, the control
unit provides the intake control.
When the fan is turned off or the A/C (air
conditioning) is turned off, the intake is fixed to
the FRESH mode.
When FC or FH is selected from the control
switch, the intake mode is accordingly fixed to
the RECIRC or FRESH.
¥ In the Manual Operation
Pressing the FRESH (fresh air intake) or the
RECIRC (room air circulation) accordingly selects
the FRESH or RECIRC mode.
¥ When the DEF Mode Switch is depressed
The intake mode is fixed to the FRESH. When
the MANU REC is selected, however, the mode
is fixed the RECIRC.
¥ When the Mode Switch is depressed
If the automatic intake control is selected, the
intake is fixed to the currently selected mode.5. Compressor Control
In the automatic control mode, the automatic
heater/air conditioner control unit turns on or off
the compressor with the evaporator anti-freeze
mechanism using the duct sensor. And, when
outside air is detected to be low through the
ambient sensor signal, the control unit turns off
the compressor using the compressor control
function.
¥ Manual Control
In the automatic control mode, pressing the A/C
(air conditioning) switch turns off the
compressor.
¥ Pressing the DEF mode switch automatically
turns on the compressor.
Intake door open / close
RECIRC Setup temperature
signal
Intake
actuator
Position
detection
switch
In car sensor
Ambient sensor
Sun sensor
Compressor
ON / OFF
Fan ON / OFF
Intake switch
Control unit
Intake door
MIX
FRESH
Heater
sideCooler
side Total mode signal
C01RY00012
Ambient sensor
Control unit
Pressure switch
Thermo switch relay
ECM
Compressor relay
Compressor
Electronic
thermostat
Air conditioning
switch
Set up temperature
signal
C01RY00010

AIR CONDITIONING 1BÐ91
6. Heating Start Timing Control
When the automatic heater/air conditioner is
started, heating is turned on under following
conditions.
·The detected temperature of thermo unit is
136¡F or less.
·The temperature setting signal and the total
signal by each sensor meet the condition of
heating.
When the detected temperature by the coolant
temperature sensor is 136¡F or less the blower
fan motor is set to work at low speed and the
"DEF" mode is selected.
When the detected temperature by the coolant
temperature sensor is 77¡F or more, the blow
mode changes automatic control. And the
blower fan speed is controlled to be lineally up
from "LO" to "MAX HI".7. Cooling Start Timing Control
When the automatic heater/air conditioner is
started, cooling is turned on under following
conditions.
·The in car sensor is 86¡F or more.
·The temperature setting signal and the signals
from each sensor meet the specified condition.
The blower fan speed is set to "LO" for
maximum 7 seconds when cooling start
conditions meet, and then, is controlled to be
lineally up to "MAX HI" by 5.32%/S.
Ignition swich
"ON"
Time
Blower voltage to turn
on the cooling
7 SEC maximum3 SEC
100%
(MAX HI)
33.5%
(LO)5.32%/S
C06RY00001
33.5%
(LO)
2.63%/S
Mode
DEF
Auto
Mode
100%
(MAX HI)
Ignition
switch "ON"
Thermo Unit 58¡C(Gasoline)
52¡C(Diesel) Time
840RY00009