Isuzu KB P190. Manual — part 34

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-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-
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) ?

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

HEATER AND AIR CONDITIONING 1-103

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)
and ground (C-109).

NO

YES

• Defective ECM

Open circuit between the No. EB-13 fuse
and the chassis side harness connector
No. 6 (B-57).

NO

1-104 HEATER AND AIR CONDITIONING

4JJ1-TC Standard Output, 4JJ1-TC High Output, 4JK1-TC High Output RHD MODEL

RTW710XF000401

HEATER AND AIR CONDITIONING 1-105

MAGNETIC CLUTCH DOES NOT RUN (4JJ1-TC Standard Output, 4JJ1-TC

High Output, 4JK1-TC High Output RHD MODEL)

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-6 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-3) 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-3) and ground?

Defective compressor

YES

NO

Defective magnetic clutch

• Is the electronic thermostat (C-55) OK?

YES

Replace

NO