2004 ISUZU TF SERIES engine

1-92 HEATER AND AIR CONDITIONING




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 4JH1TC No.4 (X-6) 4JA1L
No. 3 (X-13) and engine room harness
connector terminal No. 4 (X-14).
NO

Is there continuity between the relay terminal
4JH1TC No. 4 (X-6) 4JA1L No.3 (X-13)and
engine room harness connector terminal No.4
(C-24)?
YES


connect the A/C thermo relay connector.
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)
dd?
Open circuit between the engine room
harness connector terminal No. 2 (C-
55) and the engine room harness
connector terminal No. 2 (C-24).
NO
YES


Is there continuity between the engine room
harness connector terminal No.1 (C-55) and
ground (C-109) ? or (cooler only) the short
connector terminal No.3 (B-79) and ground (C-
109
)?
Open circuit between the No. EB-13
fuse and engine room harness
connector terminal No. 3 (C-55).
NO


Disconnect the electronic themostat.


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 and engine room
harness connector terminal No. 3 (X-
15) and the engine room harness
connector terminal No. 1(C-24).
NO

HEATER AND AIR CONDITIONING 1-93



YES


Disconnect the A/C switch.


Is there battery voltage between the chassis side
harness connector terminal No. 6 (B-57) and ground (C-
109)?
Open circuit between the engine room
harness connector terminal No. 1 (C-55) or
(cooler only) the short connector No. 3 (B-
79) and ground (C-109).
NO YES

Is there continuity between the engine room harness
connector (cooler only) terminal No. 4 (C-55) and the
chassis side harness connector terminal No. 11 (B-57).
Open circuit between the engine room
harness connector (cooler only) terminal
No. 4 (C-55) and the chassis side harness
connector terminal No. 11 (B-57).
NO YES

Is there battery voltage between the chassis side
harness connector terminal No. 10 (B-57) and ground?
Open circuit between the chassis side
harness connector No. 1 (B-79) and
chassis side harness connector terminal
No. 10 (B-57).
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

HEATER AND AIR CONDITIONING 1-95

MAGNETIC CLUTCH DOES NOT RUN


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 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

1-96 HEATER AND AIR CONDITIONING




Open circuit between the engine
harness connector terminal No.1 (E-
13) and 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. 11 (E-61) and engine
room harness connector terminal No.4 (X-14)?
NO
Open circuit between the No. EB-13
fuse and engine room harness
connector terminal No.1 (X-14).
NO
Open circuit between the No.EB-13
fuse and 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 No.31 (E-61) and engine
room harness connector terminal No.1 (X-15)? Open circuit between the ECM
harness connector No. 11 (E-61) and
engine room harness connector
terminal No. 4 (X-14).
NO
YES

Is there battery voltage between the engine room
harness connector terminal No.3 (X-15) and
ground?
Open circuit between the No. EB-13
fuse and engine room harness
connector terminal No. 2 (X-15).
NO
YES

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 engine room harness
connector terminal No. 3 (X-15).
NO


Disconnect the ECM harness connector.

Disconnect the pressure switch.

HEATER AND AIR CONDITIONING 1-97



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.4 (X-6) 4JAH No. 3 (X-
13) and engine room harness
connector terminal No. 4 (X-14).
NO

Is there continuity between the relay terminal
No. 4 (X-6) and engine room harness connector
terminal No.4 (C-24)?
YES

connect the A/C thermo relay connector.
Open circuit between the No. EB-13
fuse and engine room harness
connector terminal No. 4 (C-24).
NO
YES

Is there battery voltage between the engine
room harness connector terminal No.3 (C-55)
dd?
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 engine room harness
connector terminal No. 3 (C-55).
NO


Disconnect the electronic themostat.


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

1-100 HEATER AND AIR CONDITIONING



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 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

HEATER AND AIR CONDITIONING 1-101



Open circuit between the No. EB-13
fuse and 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 No. 14 (C-56) and engine
room harness connector terminal No.4 (X-14)?
Open circuit between the No. EB-13
fuse and 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 No. 26 (C-56) and engine
room harness connector terminal No. 1 (X-15)?Open circuit between the ECM
harness connector No.14 (C-56) and
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 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. 4 (X-15).
NO


Disconnect the ECM harness connector.

Disconnect the pressure switch?
Open circuit between the engine harness
connector terminal No.1 (E-3) and engine
room harness connector terminal No.2 (X-
14).
NO

1-102 HEATER AND AIR CONDITIONING



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-7) and engine room harness
connector terminal No. 4 (X-14).
NO

Is there continuity between the relay terminal No. 3 (X-7)
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. 4 (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 (CX-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 engine room harness connector
terminal No. 2 (X-15).
NO


Connect the A/C thermo relay connector.


Disconnect the electronic thermostat.