Isuzu KB P190. Manual — part 33

1-98 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 (C-
109)?

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 the
chassis side harness connector terminal
No. 10 (B-57).

NO

YES

• Defective ECM

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

NO

HEATER AND AIR CONDITIONING 1-99

4JH1 – TC

RTW710XF000301

1-100 HEATER AND AIR CONDITIONING

MAGNETIC CLUTCH DOES NOT RUN (4JH1-TC)

Replace

YES

• Are the A/C thermo (X-15) and 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

HEATER AND AIR CONDITIONING 1-101

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.38 (C-56) 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.2 (X-
15) and the engine room harness
connector terminal No. 3 (X-14).

NO

• Is there continuity between the engine room
harness connector terminal No.3 (X-14) and No.2
(X-15)?

YES

• Is there continuity between the ECM harness
connector terminal No.33 (C-56) and the engine
room harness connector terminal No.1 (X-15)?

Open circuit between the ECM
harness connector terminal No.38 (C-
56) 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.3 (X-15) and
ground?

Open circuit between the ECM
harness connector No. 33 (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. 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. 3 (X-15).

NO

• Disconnect the ECM harness connector.

• Disconnect the pressure switch?