1998 ISUZU TROOPER heating

HEATING AND VENTILATION 1A Ð 29
REMOVAL
Preparation:
Disconnect the battery ground cable
1. Front console assembly
2. Lower cluster assembly
3. Glove box
4. Instrument panel passenger lower cover
Refer to Section 10 ÒBODYÓ for INSTRUMENT PANEL
ASSEMBLY removal procedure.
5. Resistor connector
6. Duct (Heater only)
7. Resistor
INSTALLATION
To install, follow the removal steps in the reverse order.

1A Ð 30 HEATING AND VENTILATION
4
4a
3
Full hot switch
Cover
Clamp
22
0


25


30AUTOA
/
CO
F
FAUTOLOHI
1
y
Removal Steps
1. Instrument panel assembly
2. Instrument panel center bracket
3. Rear heater duct
4. Ceramic heater assembly
4a. Full hot switch
CERAMIC HEATER AND/OR FULL HOT SWITCH
Installation Steps
To install, follow the removal steps in
the reverse order.
This illustration is based on RHD

HEATING AND VENTILATION 1A Ð 31
REMOVAL
Preparation:
Disconnect the battery ground cable
1. Instrument panel assembly
Refer to Section 10 ÒBODYÓ for ÒINSTRUMENT
PANEL ASSEMBLYÓ removal procedure.
2. Instrument panel center bracket
Refer to Section 10 ÒCROSS BEAM ASSEMBLYÓ
removal procedure.
3. Rear heater duct
4. Ceramic heater
1) Disconnect the connector and remove the heater
fixing screw and heater harness fixing clamps.
2) Pull the ceramic heater out from heater unit.
4a. Full hot switch
Disconnect the switch connector and remove the
switch fixing screw and switch harness fixing clamp.
INSTALLATION
To install, follow the removal steps in the reverse order,
noting the following points.
1. The installation should be made with care so that
there is continuity between the switch side connector
terminals when the knob is set to the ÒFull HotÓ
position.
2. Be sure to handle the EGR and the ABS control unit
with care to avoid the disengagement of connectors.

1BÐ74 AIR CONDITIONING
FUNCTIONS AND FEATURES
¥ Automatic interior temperature control
This function enables to maintain the interior temperature at the level specified from the temperature
control switch despite of changes in factors such as vehicle speeds, outside air temperature and number
of passengers.
¥ Maximum cooling and heating function
You can select FC (Full cool, namely maximum cooling temperature) or FH (Full heat, maximum heating
temperature) from the temperature control lever.
¥ Automatic air flow control
Air flow is automatically and consecutively fine tuned according to the specified interior temperature and
changes in aperture of the heater unit mix door.
¥ Mode (blow port) control
This function automatically selects either one of the VENT, BI-LEVEL, FOOT or DEP mode for the blow
port according to changes of temperature on the blow port. Using the mode switch allows you to select a
desired blow port manually.
¥ Intake (switching between the fresh air intake and circulation of interior air) control
The intake (switching between fresh air intake and circulation of interior air) mode automatically selects
either FRESH (fresh air intake), MIX or RECIRC (interior air circulation) according to changes of the blow
port temperature. Using the intake switch allows you to select a desired intake port manually (in the
manual operation, FRESH and RECIRC modes alone are available). Pressing the DEF (defrost) mode
switch selects the FRESH (fresh air intake).
¥ Cooler start-up timing control
This function is used for maintaining the air flow at "LOW" level until the evaporator is sufficiently cooled
down. It is intended to prevent a large volume of hot air being blowing into inside of a vehicle when the
cooler is turned on in hot summer season.
¥ Heater start-up timing control
This function is used for maintained the air flow at "LOW" level and also for maintaining the defrost
mode until temperature of coolant in the heater core is sufficiently heated. It is intended to prevent a
large volume of cool air being blown into inside of a vehicle when the heater is turned on in cold winter
season.
¥ Solar radiation quantity offset control
The photodiode on the solar radiation sensor determines solar radiation quantity accurately to offset
interior temperature quickly.
¥ Switch position storing function
This function is used for storing switch positions being selected in the immediately preceding operation,
namely the last time the ignition has been turned off. It simplifies the setup procedures when restarting
the system.
¥ Self-diagnosis function
The self-diagnosis function turned on from the panel switch makes your troubleshooting easier (for detail
of this function, refer to the section titled "Self-Diagnosis").

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

1BÐ92 AIR CONDITIONING
TROUBLESHOOTING
Troubleshooting, Its Overview and Procedures
The full automatic heater and air conditioner equips with the "Self-Diagnosis Function" to check its major
components.
This function makes access to the sensors, actuators and blower fan motor system easier when checking
them up and, when a failed part is located, this function restores its original performance.
When implementing the troubleshooting, this self-diagnosis function narrows the range to be searched at
the first step, then check relevant parts one by one according to the "Checking Procedures by Failed
Location" As for a location this function is unappreciable, the system accurately determines characteristics
of a given trouble and checks relevant parts according to the "Checking Procedures by Failed Location".
The following illustrates basic troubleshooting flow.
1. Basic Troubleshooting Flow
Occurrence of a trouble
Refer to the check list for
the inspection.Locate the failed location.
Check the failed part.
Correction
Correction
Correction
Troubleshooting by the
self-diagnosis function.Reference the "Check
Procedure by Failed
Location" for the inspection.
Reference the "Check
Procedure by Failed
Location" for the inspection.Correction
Check the cooling / heating
cycles.
End OK OK OK OKNG
NG
NG
NG
NG OK
Check if the automatic
heater / air conditioner
control unit indicator LED
is turned on.Check the power supply and
circuit on the automatic
heater / air conditioner control
unit.
Troubleshooting not relying
on the self-diagnosis
function(troubleshooting
by failure type).
F01RX009

6A±11
ENGINE MECHANICAL
Condition CorrectionPossible cause
Engine overheatingLevel of Engine Coolant too lowReplenish
Fan clutch defectiveReplace
Incorrect fan installedReplace
Thermostat defectiveReplace
Engine Coolant pump defectiveCorrect or replace
Radiator cloggedClean or replace
Radiator filler cap defectiveReplace
Level of oil in engine crankcase too
low or wrong engine oilChange or replenish
Resistance in exhaust system
increasedClean exhaust system or replace
defective parts
Throttle Position Sensor adjustment
incorrectReplace with Throttle Valve ASM
Throttle Position Sensor circuit open
or shortedCorrect or replace
Cylinder head gasket damagedReplace
Engine overcoolingThermostat defectiveReplace (Use a thermostat set to
open at 82
C (180
F))
Engine lacks compressionÐÐÐÐRefer to Hard Start
OthersTire inflation pressure abnormalAdjust to recommended pressures
Brake dragAdjust
Clutch slippingAdjust or replace
Level of oil in engine crankcase too
highCorrect level of engine oil
Exhaust Gas Recirculation Valve
defectiveReplace
Engine Noisy
Abnormal engine noise often consists of various noises
originating in rotating parts, sliding parts and othermoving parts of the engine. It is, therefore, advisable to
locate the source of noise systematically.
Condition
Possible causeCorrection
Noise from crank journals or from
crank bearings
(Faulty crank journals and crankOil clearance increased due to worn
crank journals or crank bearingsReplace crank bearings and
crankshaft or regrind crankshaft and
install the undersize bearing
yj
bearings usually make dull noise that
becomes more evident when
accelerating)Crankshaft out of roundReplace crank bearings and
crankshaft or regrind crankshaft and
install the undersize bearing
Crank bearing seizedCrank bearing seized. Replace crank
bearings and crankshaft or regrind
crankshaft and install the undersize
bearing
Troubleshooting Procedure
Short out each spark plug in sequence using insulated
spark plug wire removers. Locate cylinder with defectivebearing by listening for abnormal noise that stops when
spark plug is shorted out.

6A±13
ENGINE MECHANICAL
Condition CorrectionPossible cause
Engine knockingPreignition due to use of spark plugs
of inadequate heat rangeInstall Spark Plugs of adequate heat
range
Carbon deposits in combustion
chambersClean
Fuel too low in octane ratingReplace fuel
Wide Open Throttle enrichment
system failureRefer to Section 6E
Selection of transmission gear
incorrectCaution operator of incorrect gear
selection
Engine overheatingRefer to ªEngine Lacks Powerº
OthersWater pump defectiveReplace
Drive belt slippingReplace auto tentioner or drive belt
Abnormal Combustion
ConditionPossible causeCorrection
Trouble in fuel systemFuel pressure control valve defectiveReplace
Fuel filter cloggedReplace
Fuel pump cloggedClean or replace
Fuel tank or fuel pipe cloggedClean or replace
Fuel injector cloggedClean or replace
Fuel pump relay defectiveReplace
Power supply cable for fuel pump
broken or poor connectionsReconnect, correct or replace
Mass Airflow (MAF) sensor circuit
open or defectiveCorrect or replace
MAF Sensor defectiveReplace
Manifold Absolute Pressure Sensor
circuit open or shortedCorrect or replace
Manifold Absolute Pressure Sensor
defectiveReplace
Engine Coolant Temperature (ECT)
Sensor circuit open or shortedCorrect or replace
ECT Sensor defectiveReplace
Throttle Position Sensor adjustment
incorrectReadjust
Throttle Position Sensor defectiveReplace
Throttle Position Sensor connector
poor connectionsReconnect
Vehicle Speed Sensor cable poor
connections or defectiveCorrect or replace
Vehicle Speed Sensor loosely fixedFix tightly
Vehicle Speed Sensor in wrong
contact or defectiveReplace
Powertrain Control Module cable
poor connections or defectiveCorrect or replace