1998 ISUZU TROOPER Coolant system

WIRING SYSTEM 8DÐ451
4. Engine Coolant Temperature (ECT) Gauge
4-1 Gauge Needle Does Not Move
·IS THE CONNECTOR OF THE ENGINE COOLANT
TEMPERATURE UNIT CONNECTED SECURELY?
YES
·
·
·DISCONNECT THE CONNECTOR OF THE ENGINE COOLANT
TEMPERATURE UNIT
CONNECT A 3.4W BULB BETWEEN THE HARNESS SIDE
CONNECTOR 1 E-19 OR 1 E-23 AND THE GROUND OF
THE ECT UNIT
WHEN THE STARTER SW IS TURNED ON, DOES THE
ECT GAUGE POINTER MOVE ABOUT 10 SECONDS
AFTER THAT?
YES
CONNECT THE CONNECTOR SECURELY
NO
NO
REPLACE THE ENGINE COOLANT
TEMPERATURE UNIT·IS THE CIRCUIT BETWEEN THE ECT GAUGE AND THE
ENGINE COOLANT TEMPERATURE UNIT NORMAL?
YES
REPLACE THE METER
ASSEMBLY
NO
REPAIR A POOR CONNECTION
AT THE CONNECTORS OR AN
OPEN CIRCUIT IN THE CIRCUIT

8DÐ452 WIRING SYSTEM
4-2 Gauge Reading Is Too Low (Or High)
·DOES THE THERMOSTAT OPERATE NORMALLY?
YES
·
·TURN THE STARTER SWITCH ON
WHEN INSERTING AND PULLING OUT THE ENGINE
COOLANT TEMPERATURE UNIT CONNECTOR 1 E-19 OR
1 E-23 SEVERAL TIMES, DOES THE INDICATION OF THE
ECT GAUGE VARY?
YES
REPLACE THE THERMOSTAT
NO
REPAIR A POOR CONNECTION AT THE CONNECTOR
OF THE ENGINE COOLANT TEMPERATURE UNIT
NO
·IS THE ENGINE COOLANT TEMPERATURE UNIT NORMAL?
YES
REPLACE THE ENGINE
COOLANT TEMPERATURE
UNIT
NO
REPLACE THE METER
ASSEMBLY

WIRING SYSTEM 8DÐ453
4-3 Needle Overshoots (Goes Up To The ÒHÓ Range)
·
·DISCONNECT THE CONNECTOR OF THE ENGINE
COOLANT TEMPERATURE UNIT
WHEN THE STARTER SW IS TURNED ON, DOES THE
POINTER REACH TO THE “H” RANGE?
YES
·IS THERE A SHORT CIRCUIT BETWEEN THE
ECT UNIT AND THE ECT GAUGE?
YES
REPLACE THE ENGINE COOLANT
TEMPERATURE UNIT
NO
REPAIR THE SHORT CIRCUIT
NO
REPLACE THE METER ASSEMBLY

WIRING SYSTEM 8D – 471
Heater and Air Conditioning
General Description
The circuit consists of pressure switch, A/C switch,
electronic thermostat, blower motor, fan switch,
magnetic clutch of A/C compressor, blower resistor
and relay.
The operation of A/C system is controlled by turning
A/C switch on and off. Electronic thermostat and PCM
can stop operation of A/C temporarily by disconnect-
ing magnetic clutch under the predetermined condi-
tions to adjust room temperature, preventing abnor-
mal rise of engine coolant and reduce engine load
while A/C is in operation.
Refer to Heating, Ventilation and Air Conditioning in
HVAC section.