Page 145 of 6020

HEATER AND AIR CONDITIONING 1-111
Open circuit between the engine
harness connector terminal No.1 (E-3)
and the engine room harness
connector terminal No.2 (X-14).
YES
• Is there battery voltage between the engine room
harness connector terminal No.1 (X-14) and
ground?
YES
• Disconnect the A/C thermo relay.
YES
• Is there continuity between the ECM harness
connector terminal No.55 (C-58) and the engine
room harness connector terminal No.5 (X-14)?
NO
Open circuit between the No. EB-13
fuse and the engine room harness
connector terminal No.1 (X-14).
NO
Open circuit between the engine room
harness connector terminal No.3 (X-
14) and the engine room harness
connector terminal No. 1 (X-15).
NO
• Is there continuity between the engine room
harness connector terminal No.3 (X-14) and the
engine room harness connector terminal No.1 (X-
15)?
YES
• Is there continuity between the ECM harness
connector terminal No.4 (C-58) and the engine
room harness connector terminal No.1 (X-15)? Open circuit between the ECM
harness connector terminal No.55 (X-
58) and the engine room harness
connector terminal No. 5 (X-14).
NO
YES
• Is there battery voltage between the engine room
harness connector terminal No.2 (X-15) and
ground? Open circuit between the ECM
harness connector terminal No. 4 (C-
58) and the engine room harness
connector terminal No. 1 (X-15).
NO
YES
• Is there continuity between the engine room
harness connector terminal No. 5 (X-15) and the
engine room harness connector terminal No. 1 (C-
24)?
Open circuit between the No. EB-13
fuse and the engine room harness
connector terminal No. 2 (X-15).
NO
• Disconnect the ECM harness connector.
• Disconnect the pressure switch.
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ISUZU KB P190 2007
Page 146 of 6020

1-112 HEATER AND AIR CONDITIONING
YES
• Disconnect the condenser fan relay.
YES
• Is there battery voltage between the engine
room harness connector terminal NO.3 (C-
24) and ground? Open circuit between the condenser
fan relay No.3 (X-9) and the engine
room harness connector terminal No.
4 (C-24).
NO
• Is there continuity between the relay terminal
No. 3 (X-9) and engine room harness connector
terminal No.4 (C-24)?
YES
Open circuit between the No. EB-13
fuse and engine room harness
connector terminal No. 3 (C-24).
NO
YES
• Is there battery voltage between the engine
room harness connector terminal No.3 (C-55)
and ground? Open circuit between the engine room
harness connector terminal No. 2 (C-
24) and the engine room harness
connector terminal No. 2 (C-55).
NO
YES
• Is there continuity between the engine room
harness connector terminal No.1 (C-55) and
ground (C-109)? Open circuit between the No. EB-13
fuse and the engine room harness
connector terminal No. 3 (C-55).
NO
• connect the A/C thermo relay connector.
• Disconnect the electronic thermostat.
• Is there continuity between the engine room
harness connector terminal No. 2 (C-55) and the
engine room harness connector terminal No. 2
(C-24)?
Open circuit between the engine room
harness connector terminal No. 5 (X-
15) and the engine room harness
connector terminal No. 1 (C-24).
NO
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ISUZU KB P190 2007
Page 147 of 6020
HEATER AND AIR CONDITIONING 1-113
YES
• Is the electronic thermostat OK?
Open circuit between the engine room
harness connector terminal No. 1 (C-55)
and ground (C-109).
NO YES
• Disconnect the A/C switch.
• Is there battery voltage between the chassis side
harness connector terminal No. 6 (B-57) and ground?
Open circuit between the No. EB-13 fuse
and the chassis side harness connector
No. 6 (B-57)
NO
YES
• Defective ECM Replace electronic thermostat
NO
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Page 148 of 6020
1-114 HEATER AND AIR CONDITIONING
C24SE
RTW 610XF000501
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ISUZU KB P190 2007
Page 149 of 6020

HEATER AND AIR CONDITIONING 1-115
MAGNETIC CLUTCH DOES NOT RUN (C24SE)
Replace
YES
• Are the A/C thermo (X-15), heater & A/C (X-11)
and A/C compressor (X-14) relay OK?
• Are the No. SBF 8 fuse (30A) and the No. EB-13
(10A) fuses OK?
YES
• Is the pressure switch (C-24) OK?
YES
• Are the A/C switch (B-57) and the fan switch (B-13)
OK?
NO
YES
• Is there continuity between the engine harness
connector terminal No.1 (E-2) and the engine room
harness connector terminal No.2 (X-14)?
• Disconnect the A/C compressor relay.
• Turn the ignition switch "ON" (Engine is running)
• A/C switch and fan control knob (fan switch "ON")
NO
Replace
NO
Defective switch or insufficient
refrigerant
NO
NO
Does the magnetic clutch
operate?
YES
Replace
• Disconnect the magnetic clutch connector.
• Is there battery voltage between the engine room
harness connector terminal No.1 (E-2) and ground?
Defective compressor
YESNO
Defective magnetic clutch
• Is the electronic thermostat (C-55) OK?
Replace
NOYES
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ISUZU KB P190 2007
Page 150 of 6020

1-116 HEATER AND AIR CONDITIONING
Open circuit between the No. EB-13
fuse and the engine room harness
connector terminal No.1 (X-14).
NO
YES
• Is there battery voltage between the engine room
harness connector terminal No.1 (X-14) and
ground?
YES
• Disconnect the A/C thermo relay.
YES
• Is there continuity between the ECM harness
connector terminal C24SE No. 14 (C-56) and the
engine room harness connector terminal No.4
(X-14)?
Open circuit between the No. EB-13
fuse and the engine room harness
connector terminal No. 3 (X-14).
NO
• Is there battery voltage the engine room harness
connector terminal No.3 (X-14) and ground?
YES
• Is there continuity between the ECM harness
connector terminal C24SE No. 26 (C-56) and the
engine room harness connector terminal No. 1
(X-15)? Open circuit between the ECM
harness connector terminal C24SE
No.14 (C-56) and the engine room
harness connector terminal No. 4 (X-
14).
NO
YES
• Is there battery voltage between the engine room
harness connector terminal No. 2 (X-15) and
ground? Open circuit between the ECM
harness connector terminal C24SE
No. 26 (C-56) and the engine room
harness connector terminal No. 1 (X-
15).
NO
YES
• Is there continuity between the engine room
harness connector terminal No. 3 (X-15) and the
engine room harness connector terminal No. 1 (C-
24).
Open circuit between the No. EB-13
fuse and engine room harness
connector terminal No. 2 (X-15).
NO
• Disconnect the ECM harness connector.
• Disconnect the pressure switch?
Open circuit between the engine harness
connector terminal No.1 (E-2) and the
engine room harness connector terminal
No.2 (X-14).
NO
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ISUZU KB P190 2007
Page 151 of 6020

HEATER AND AIR CONDITIONING 1-117
YES
• Disconnect the condenser fan relay connector condenser
fan.
YES
• Is there battery voltage between the engine room
harness connector terminal NO. 3 (C-24) and ground?Open circuit between the condenser fan
relay No.3 (X-10) and engine room harness
connector terminal No. 4 (C-24).
NO
• Is there continuity between the relay terminal No. 3 (X-
10) and engine room harness connector terminal No.4
(C-24)?
YES
Open circuit between the No. EB-13 fuse
and engine room harness connector
terminal No. 3 (C-24).
NO
YES
• Is there continuity between the engine room harness
connector terminal No. 2 (C-55) and the engine room
harness connector terminal No. 2 (C-24)?
Open circuit between the engine room
harness connector terminal No. 4 (X-15)
and the engine room harness connector
terminal No. 1 (C-24).
NO
• Disconnect the pressure switch.
• Is there continuity between the engine room harness
connector terminal No. 4 (X-15) and the engine room
harness connector terminal No. 1 (C-24).
Open circuit between the No. EB-13 fuse
and the engine room harness connector
terminal No. 2 (X-15).
NO
• Connect the A/C thermo relay connector.
• Disconnect the electronic thermostat.
Open circuit between the engine room
harness connector terminal No.3 (X-15)
and the engine room harness connector
terminal No. 1 (C-24).
NO
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ISUZU KB P190 2007
Page 152 of 6020
1-118 HEATER AND AIR CONDITIONING
YES
• Disconnect the A/C switch.
• Is there battery voltage between the chassis side
harness connector terminal No. 6 (B-57) and ground?
Open circuit between the engine room
harness connector terminal No. 2 (C-24)
and the engine room harness connector
terminal No. 2 (C-55).
NO YES
• Is there battery voltage between the engine room
harness connector terminal No. 3 (C-55) and ground?
Open circuit between the No. EB-13 fuse
and the engine room harness connector
terminal No. 3 (C-55).
NO YES
• Is there continuity between the engine room harness
connector terminal No. 1 (C-55) and ground (C-109)?
Open circuit between the engine room
harness connector No. 1 (C-55) and ground
(C-109).
NO
YES
• Is the electronic themostat OK? Open circuit between the No. EB-13 fuse
and the chassis side harness connector
No. 6 (B-57).
NO
YES
• Defective ECM Replace electronic thermostat
NO
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ISUZU KB P190 2007