1998 ISUZU TROOPER Intake sensor

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.


;&9&-
"650
"$0''"650-0)*
21
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

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

1BÐ98 AIR CONDITIONING
*1. Displaying the Current Trouble Diagnosing Table
Start the engine while holding down both the Auto switch and the DEF switch on the control panel, and
the table will appear in approximately 10 seconds to the indicator lamp (LED) of the air conditioning
switch. Result of the diagnosis along the following 9 items will be shown one by one in 0.5 second
interval irrespective of presence or absence of a trouble for a given item. When the display 9 items is
completed, it is repeated with 3 seconds of interval in between. A failed item is indicated by flashing of
the LED that is repeated 3 times within 0.5 seconds. If a trouble is indicated, you can locate the failed
section by knowing when in the total sequence it has been displayed.
Items for Current Trouble Diagnosis
As shown above, display of result along nine items is repeated with 3-second interval in between.
Note 1: When checking the solar radiation sensor, apply sufficient light using a 60W bulb.
Otherwise, it can be diagnosed as failed.
Note 2: If the temperature setting lever is set on both ends (one set to 18¡C, blue scale = Full cool and
the other to 31¡C, red scale = Full hot), they can be diagnosed as failed.
Note 3: Likewise, the fan switch can be diagnosed as failed if set on both ends.
LED on
LED off Indication for presence
of a troubleIndication for normal state
0.5 0.5 0.5
3 seconds interval
ON
OFF
Display pattern Failed part
Normal pattern
In car sensor
Ambient sensor
Sun sensor (Note 1)
Duct sensor
Temperature control lever (Note 2)
Fan switch (Note 3)
Mix actuator
Mode (blow port) control
Intake (fresh air/interior air switching) control
F01RX010
F01RY00008

AIR CONDITIONING 1BÐ99
*2. Displaying the Past Trouble Diagnosing Table
The past trouble diagnosis displays only the items on which trouble has recurred 16 times in the past.
If you press the air conditioning switch once while the current trouble diagnosis is taking place, display
of the past trouble diagnosis will appear on the indicator lamp (LED) of the air conditioning switch.
Results of the diagnosis along the following five items are displayed one by one in 0.5 second interval
irrespective of presence or absence of a trouble. A failed item is indicated by flashing of the LED that is
repeated 3 times within 0.5 seconds. You can locate the failed section by counting in what sequence it
has been displayed.
Items for Past Trouble Diagnosis
LED on
LED off Indication for presence of a trouble Indication for normal state
0.5 0.5 0.5
3 second interval
Display pattern
ON
OFFNormal pattern
In car sensor
Ambient sensor
Sun sensor
Duct sensor
Mix actuatorFailed part
F01RX011
F01RY00007
*3. Check of Output Equipment
FAN
MIX
MODE
DOOR
INTAKE
DOOR
SET UP
TEMPERATURE
100
(%)
33.5
F/H
VENT
B/L
FOOT
D/F
DEF
REC
MIX
FRE
F/C 20 21 22 23 24 25 26 27 28 29 30 F/H (%)
F/C
F01RY00001

1BÐ118 AIR CONDITIONING
Inspection of the Magnet Clutch System
6VE1 Engine
I-32
C-1C-3I-33
E-3E-19
12345678
9 10111213141516
1
112
123
134
145
156
167
178
189
1910
20
B-19C-25
A 2
B-361
H-14
C-19
25A
BLOWER
MOTOR
C-20
10A
A/C FL-1
80A
MAIN
Heater
Relay
1B-3610
H-13
0.3
B 0.85
W/G0.85
W/R
3.0
W
3.0
L/R
0.5
BR
1.25
B
B-19
BODY-LH3
B-36
4B-36
BATT.(+)
Blower
MotorIntake
Actuator STARTER
RELAY(1)
0.5
LG 0.5
BR0.5
BR
0.5
G/W
0.5
P/G0.5
P/G0.5
G/O
0.5
G/O
PCM
(C3-E15)
31 13
COMP-F/B 70.5
BR
0.5
BR/Y 0.3
G/B0.5
G/B0.5
BR/Y 0.5
BR
Triple
Pressure
Switch
0.5
BR
A
A/C
Thermo Relay
Auto A/C Control Unit
3X-5
16
H-1617H-16
14
I-3218I-33
1X-5
13H-24
12
H-41
2 1
C-25
C-25
4X-5X-5 2
X-57
H-16
A/C
Compressor
Relay
Magnetic
clutch
1X-7
3X-74X-72
X-7
PCM
(C-1-B14)
E-39
1
H-67
H-41
5
H-41
Engine
Coolant
Temperature
Sensor
ENGINE COOLANT
TEMPERATURE GAUGE
0.5
Y/B
0.5
Y/B
0.5
Y/B
E-1911
1
H-61
H-24
I-334
B-36X-5X-7
H-14
1
2
1
2
H-16
H-24
H-13
H-6H-41
12
3412111
362
51
4 123
45 610987654321
22212019181514131211171612345111213141567891018192021221617
6H-41
4321
8765
12 11 10 9
16 15 14 13123 4
567 8
9101112
13 14 15 16
17 18 16 15 1478 6 5
12 13 11 10 94 132
5 6 7 8
15 16 17 18 142 3 41
10 11 12 13 9A1 A2 A3 A4 A5 A6 A7 A8 A9A10 A11 A12 A13 A14 A15 A16B1 B2 B3 B4 B5 B6 B7 B8 B9B10 B11 B12 B13 B14 B15 B16E1 E2 E3 E4 E5 E6 E7 E8 E9E10 E11 E12 E13 E14 E15 E16F1 F2 F3 F4 F5 F6 F7 F8 F9F10 F11 F12 F13 F14 F15 F16
D08RY00182

COMPRESSOR OVERHAUL 1D Ð 3
solvent, and dried with dry air. Use only lint free
cloths to wipe parts.
The operations described below are based on
bench overhaul with compressor removed from the
car, except as noted. They have been prepared in
order of accessibility of the components. When the
compressor is removed from the car for servicing,
the oil remaining in the compressor should be
discarded and new refrigerant oil added to the
compressor.
Magnetic clutch assembly repair procedures require
that the system be discharged of refrigerant. (Refer
to Section 1B for ÒREFRIGERANT RECOVERYÓ.)
Compressor malfunction will appear in one of four
ways: noise, seizure, leakage or low discharge
pressure. Resonant compressor noises are not
cause for alarm; however, irregular noise or rattles
may indicate broken parts or excessive clearances
due to wear. To check seizure, de-energize the
magnetic clutch and check to see if the drive plate
can be rotated. If rotation is impossible, the
compressor is seized. Low discharge pressure may
be due to a faulty internal seal of the compressor,
or a restriction in the compressor. Low discharge
pressure may also be due to an insufficient
refrigerant charge or a restriction elsewhere in the
system. These possibilities should be checked prior
to servicing the compressor. If the compressor is
inoperative, but is not seized, check to see if current
is being supplied to the magnetic clutch coil
terminals.
The compressor has vanes built into a rotor which
is mounted on a shaft.
When the shaft rotates, the vanes built into the
cylinder block assembly are opened by centrifugal
force.
This changes the volume of the space formed by
the rotor and cylinder, resulting in the intake and
compression of the refrigerant gas. The discharge
valve and the valve stopper, which protects the
discharge valve, are built into the cylinder block
assembly. There is no suction valve but a shaft seal
is installed between the shaft and head; a trigger
valve, which applies back pressure to the vanes, is
installed in the cylinder block and a refrigerant gas
temperature sensor is installed in the front head.
The specified quantity of compressor oil is
contained in the compressor to lubricate the various
parts using the refrigerant gas discharge pressure.
6VD1 engine is equipped with an invariable
capacity five-vane rotary compressor (DKV-14D
Type).
The compressor sucks and compresses refrigerant
by the rotation of the vane installed to the shaft,
and always discharges a fixed amount of refrigerant
independent of the load of refrigerant.The thermo sensor is installed to the front head of
the compressor to protect it by stopping its
operation when the refrigerant gas is insufficient or
when the temperature get abnormally high.
·OFF ..... 160 ±5¡C (320.0 ±9.0¡F)
·ON ..... 135 ±5¡C (275.0 ±9.0¡F)
4JG2 Engine are provided with a swash plate type
compressor (DKS-15CH Type)
Swash plate compressors have a swash (slanted)
plate mounted on the shaft. When the shaft turns,
the rotation of the swash plate is converted to
reciprocating piston motion which sucks in and
compresses the refrigerant gas.
Shaft seal (Lip type) is installed between the valve
plate and shaft & cylinder head to prevent
refrigerant gas leaks. A specified amount of
compressor oil is contained in the oil pan.
This oil is supplied to the cylinders, bearings, etc.,
by an oil pump which is connected to the swash
plate shaft.
With some compressors the differential between
the intake pressure and discharge pressure
generated while the compressor is operating is
used for lubrication instead of an oil pump.
Three pistons are arranged at 120g intervals around
the center of the swash plate shaft. These pistons
are connected to the ends of the swash plate
through shoe disks and balls.
The rotation of the swash plate causes
reciprocating movement of the piston inside the
cylinders, with each piston operating as two
cylinders. Because of that, the compressor operates
as though it has 6 cylinders.
The specified amount of the compressors oil is
150cc (4.2 Imp fl oz).
Also, compressor oil to be used varies according to
the compressor model. Be sure to avoid mixing two
or more different types of oil.
If the wrong oil is used, lubrication will be poor and
the compressor will seize or malfunction.