1998 ISUZU TROOPER relay

00 Ð 22 SERVICE INFORMATION
CERAMIC HEATER DOES NOT STOP
WHEN THE IGNITION SW. ÒOFFÓ, DOES CERAMIC HEATER
STOP?
YESNO
CERAMIC HEATER RELAY DEFECTIVE·SHORT CIRCUIT BETWEEN CHASSIS SIDE RELAY TERMINAL
NO. X12-3 AND CHASSIS SIDE CONNECTOR TERMINALNO. B49-1

SERVICE INFORMATION 00 Ð 27
MAGNETIC CLUTCH
When the A/C switch and the fan control knob (fan
switch) are turned on with the engine running,
current flows through the thermostat and the com-
pressor relay to activate the magnetic clutch.
The air conditioning can be stopped by turning off
the A/C switch or the fan control knob (fan switch).
However, even when the air conditioning is in oper-ation, the electronic thermostat, the pressure switch
or the PCM (6VD1/6VE1 Engine) is used to stop the
air conditioning temporarily by turning off the mag-
netic clutch in the prearranged conditions to reduce
the engine load which is being caused by the rise in
the engine coolant temperature, and the accelera-
tion of the vehicle, etc.
123
45 6
RELAY; A/C
B-36C-20
10A
A/C FL-1
80A
MAIN
1
2
B-2
C-25
2
4
X-5
1
3 (3)
(1)
4
13
24
1
A/C SW.
FAN SW.
I-23
PRESSURE
SW.
RELAY;
THERMOSTAT
B-2
X-7 C-25
C-1C-3E-3I-23
BATTERY
X-7
RELAY: A/C
COMPRESSOR
1
E-3
MAGNETIC
CLUTCHMg
OFF
I-18
2
6
1
321123
12
3412
11
213
5 46
I-18
X-5
B-1(LHD) (RHD)
B-1
1
2 34
W/ CONDENSER
FAN
2
4
1
3
C-3PCM (E15)
C-1PCM (B14)
3
1
2
ELECTRONIC
THERMOSTAT
I-42
I-42B-36
Pin number with ( ); RHD
A1 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
6VD1/6VE1 ENGINE
D08RY00295

00 Ð 28 SERVICE INFORMATION
MAGNETIC CLUTCH DOES NOT RUN
·TURN THE STARTER SWITCH ON AND START THE
ENGINE.
·TURN THE FAN SWITCH ON.
·DOES THE BLOWER MOTOR RUN?
YESNO
REFER TO THE DIAGNOSIS PROCEDURE FOR
ÒBLOWER MOTOR DOES NOT RUNÓ.·IS THE FUSE C-20 (10A) NORMAL?
YESNO
REPLACE THE FUSE.·DISCONNECT THE A/C SWITCH CONNECTOR AND
REMOVE THE A/C SWITCH.
·IS THE A/C SWITCH NORMAL?
YESNO
YESNO
REPAIR AN OPEN CIRCUIT BETWEEN THE
FUSE C-20 AND I23-2.·REINSTALL THE A/C SWITCH AND DISCONNECT THE DUAL
PRESSURE SWITCH (OR TRIPLE PRESSURE SWITCH) CON-
NECTOR C25.
·TURN THE A/C SWITCH ON.
·IS THE BATTERY VOLTAGE APPLIED AT HARNESS SIDE
CONNECTOR C25-1?
YESNO
REPLACE THE SWITCH.·RECONNECT THE CONNECTOR C25 AND DISCONNECT THE
A/C THERMO RELAY CONNECTOR X5.
·IS THERE CONTINUITY BETWEEN HARNESS SIDE CONNEC-
TOR C25-2 AND X5-1?
YESNO
REPAIR AN OPEN CIRCUIT BETWEEN I23-6
AND C25-1.·IS THE DUAL PRESSURE SWITCH (OR TRIPLE PRESSURE
SWITCH) NORMAL?
YESNO
REPAIR OR REPLACE THE SWITCH.·IS THE BATTERY VOLTAGE APPLIED AT HARNESS SIDE
CONNECTOR I23-2?

SERVICE INFORMATION 00 Ð 29
·IS THE BATTERY VOLTAGE APPLIED AT HARNESS SIDE
CONNECTOR X5-2?REPAIR AN OPEN CIRCUIT.
YESNO
·IS THE A/C THERMO RELAY NORMAL?REPAIR AN OPEN CIRCUIT BETWEEN THE
FUSE C-20 AND X5-2.
YESNO
·DISCONNECT THE ELECTRONIC THERMOSTAT CONNEC-
TOR I42.
·IS THE BATTERY VOLTAGE APPLIED AT HARNESS SIDE
CONNECTOR I42-3?
YESNO
·IS THERE CONTINUITY BETWEEN HARNESS SIDE CON-
NECTOR X5-3 AND I42-1?REPAIR AN OPEN CIRCUIT BETWEEN I23-6
AND I42-3.
YESNO
·DISCONNECT THE PCM CONNECTORS.
·IS THERE CONTINUITY BETWEEN HARNESS SIDE CON-
NECTOR X5-4 AND PCM C3-E15?REPAIR AN OPEN CIRCUIT.
YESNO
·IS THERE CONTINUITY BETWEEN HARNESS SIDE CON-
NECTOR I42-2 AND THE GROUND?REPAIR AN OPEN CIRCUIT.
YESNO
·DISCONNECT THE A/C COMPRESSOR RELAY CONNEC-
TOR X7.
·IS THE BATTERY VOLTAGE APPLIED AT HARNESS SIDE
CONNECTOR X7-1 AND X7-2?REPLACE THE ELECTRONIC THERMOSTAT.
YESNO
·RECONNECT X5 AND I42.
·IS THE BATTERY VOLTAGE APPLIED AT HARNESS SIDE
CONNECTOR PCM C3-E15?REPAIR AN OPEN CIRCUIT.
REPLACE THE RELAY.

SERVICE INFORMATION 00 Ð 31
4JG2 ENGINE
123
45 6
RELAY; A/C
B-36C-20
(LHD) 10A
A/C FL-1
80A
MAIN
1
2
B-2
C-25
2
4
X-5
1
3
4
13
24
1
A/C SW.
FAN SW.
I-23
PRESSURE
SW.
RELAY;
THERMO
B-2
C-25E-3I-23
BATTERY
3
1
2ELECTRONIC
THERMOSTAT
1
E-3
MAGNETIC
CLUTCHMg
OFF
I-18
2
6
1
321123
12
34
121
213
5 46
I-18
X-5
B-1
(LHD)
(RHD)
B-1
1
2 34
W/ CONDENSER
FAN
I-42
I-42B-36
D08RY00169

00 Ð 32 SERVICE INFORMATION
MAGNETIC CLUTCH DOES NOT RUN
·ARE NO. C-20 (10A) FUSE AND NO. C-19 (25A) FUSES OK?
YESNO
REPLACE·ARE HEATER & A/C (B-36) AND THERMOSTAT (X-5)
RELAYS OK?
YESNO
REPLACE·IS PRESSURE SWITCH (DUAL PRESSURE SWITCH) OK?
YESNO
SWITCH DEFECTIVE OR INSUFFICIENT REFRIGERANT·ARE A/C SWITCH AND FAN CONTROL KNOB (FAN
SWITCH) OK?
YESNO
REPLACE·TURN THE IGNITION SWITCH ÒONÓ (ENGINE IS
RUNNING)
·A/C SWITCH AND FAN CONTROL KNOB (FAN SWITCH
ÒONÓ
·CHECK TO SEE IF BATTERY VOLTAGE IS PRESENT AT
CHASSIS SIDE CONNECTOR TERMINAL NO. E3-1
NOYES
MAGNETIC CLUTCH DEFECTIVE ·CHECK TO SEE IF BATTERY VOLTAGE IS PRESENT AT
CHASSIS SIDE CONNECTOR TERMINAL NO. C25-1
YESNO
OPEN CIRCUIT BETWEEN NO. C-20 (10A) FUSE AND
NO. C25-1·DISCONNECT THERMO RELAY (X-5)
·CHECK TO SEE IF BATTERY VOLTAGE IS PRESENT AT
CHASSIS SIDE RELAY TERMINAL NO. X5-2
YESNO
OPEN CIRCUIT BETWEEN NO. C25-2 AND NO. X5-2 ·CHECK TO SEE IF VOLTAGE (APPROX. 10V) IS PRESENT
CHASSIS SIDE RELAY TERMINAL NO. X5-1 AND
NO. X5-3
CONTINUED NEXT PAGE

SERVICE INFORMATION 00 Ð 33
CONTINUED PREVIOUS PAGE
NOYES
·CHECK TO SEE IF BATTERY VOLTAGE IS PRESENT AT
CHASSIS SIDE RELAY TERMINAL NO. X5-1OPEN CIRCUIT BETWEEN NO. X5-4 AND NO. E3-1
YESNO
·RECONNECT THERMO RELAY
·CHECK TO SEE IF BATTERY VOLTAGE IS PRESENT AT
CHASSIS SIDE CONNECTOR TERMINAL NO. I42-3
·CHECK TO SEE IF BATTERY VOLTAGE IS PRESENT AT
CHASSIS SIDE CONNECTOR TERMINAL NO. I23-2
NOYES
OPEN CIRCUIT BETWEEN
NO. C-20 (10A) FUSE AND
NO. I23-2OPEN CIRCUIT BETWEEN
X5-1 AND NO. I23-6NOYES
·CHECK TO SEE IF BATTERY VOLTAGE (APPROX. 10V)
IS PRESENT AT CHASSIS SIDE CONNECTOR TERMINAL
NO. I42-1
YESNO
·CHECK TO SEE IF BATTERY VOLTAGE IS PRESENT AT
CHASSIS SIDE CONNECTOR TERMINAL NO. I42-2OPEN CIRCUIT BETWEEN NO. X5-3 AND NO. I42-1
YESNO
·OPEN CIRCUIT BETWEEN NO. I42-2 AND NO. I18-4 OR
POOR GROUND (FAN SWITCH GROUND CIRCUIT)ELECTRO THERMO DEFECTIVE
OPEN CIRCUIT BETWEEN
NO. I23-6 AND NO. I42-3

00 Ð 34 SERVICE INFORMATION
4JX1 ENGINE
123
45 6
RELAY; A/C
B-36C-20
10A
A/C FL-1
80A
MAIN
1
2
B-2
C-25
2
4
X-5
1
3
4
13
24
1
A/C SW.
FAN SW.
I-23
PRESSURE
SW.
RELAY;
THERMO
B-2
C-25I-23
BATTERY
1
E-27
MAGNETIC
CLUTCHMg
OFF
I-18
2
6
1
321123
12
34
12
213
5 46
I-18
X-5
B-1(LHD) (RHD)
3
1
2ELECTRONIC
THERMOSTAT
I-42
B-1
1
2 34
W/ CONDENSER
FAN
I-42B-36
E-27
11
D08RY00170