Isuzu KB P190. Manual — part 35

1-106 HEATER AND AIR CONDITIONING

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 (C-
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.

HEATER AND AIR CONDITIONING 1-107

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) ? or (cooler only) the short
connector terminal No.3 (B-79) 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

1-108 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. 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 the
chassis side harness connector terminal
No. 10 (B-57).

NO

YES

• Is the electronic thermostat 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 1-109

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

RTW710XF000501