Isuzu KB P190. Manual — part 32

1-94 HEATER AND AIR CONDITIONING

4JA1 – T

RTW710XF000201

HEATER AND AIR CONDITIONING 1-95

MAGNETIC CLUTCH DOES NOT RUN (4JA1-T)

Replace

YES

• Are the A/C thermo (X-15) and heater & A/C (X-11)
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

• 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

• Disconnect the A/C thermo relay.

• Is there continuity between the engine room harness
connector terminal No.1 (E-3) and engine room harness
connector terminal No.1 (X-15)?

1-96 HEATER AND AIR CONDITIONING

Open circuit between the engine room
harness connector terminal No.1 (X-
15).

NO

YES

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

YES

• Is there battery voltage between the engine room
harness connector terminal No.3 (X-15) and
ground?

Open circuit between the engine room
harness connector terminal No. 2 (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. 2 (C-
24)?

Open circuit between the No. EB-13
fuse and the engine room harness
connector terminal No. 3 (X-15).

NO

• Disconnect the pressure switch.

• Disconnect the condenser fan relay connector
condenser fan.

• Is there battery voltage between the engine room
harness connector terminal No.4 (C-24) and
ground?

Open circuit between the condenser
fan relay No. 3 (X-13) and engine
room harness connector terminal No.3
(C-24).

• Is there continuity between the relay terminal
No.3 (X-13)and engine room harness connector
terminal No.3 (C-24)?

Open circuit between the engine room
harness connector terminal No. 5 (X-
15) and the engine room harness
connector terminal No. 2 (C-24).

YES

NO

YES

NO

HEATER AND AIR CONDITIONING 1-97

YES

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)
and ground?

Open circuit between the engine room
harness connector terminal No. 2 (C-
55) and the engine room harness
connector terminal No. 1 (C-24).

NO

YES

• Is there continuity between the engine room
harness connector terminal No.1 (C-55) and the
chassis side harness connector terminal No.5
(B-57) ? or (cooler only) the short connector
terminal No.3 (B-79) and the chassis side
harness connector terminal No.5 (B-57)?

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. 1
(C-24)?

Open circuit between the engine room
harness connector terminal No. 1 (C-
55) or (cooler only) the short
connector No. 3 (B-79) and the
chassis side harness connector
terminal No.5 (B-57).

• 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)?

YES

NO