Subaru Legacy III (2000-2003 year). Manual — part 278

CO(H6DO)-10

COOLING

RADIATOR MAIN FAN SYSTEM

18

CHECK POWER SUPPLY TO MAIN FAN MO-
TOR.

CAUTION:

Be careful not to overheat engine during re-
pair.

1) Turn ignition switch to OFF.
2) Disconnect main fan motor connector.
3) Start the engine, and perform checking pro-

cedure during coolant temperature is 98 —
101

°

C (208 — 214

°

F).

4) Measure voltage between main fan motor

connector and chassis ground.

Connector & terminal

(F17) No. 1 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Go to step 19.

Go to step 21.

19

CHECK POOR CONTACT.
Check poor contact in main fan motor connec-
tor.
Is there poor contact in main fan motor con-
nector?

There is poor contact.

Repair poor con-
tact in main fan
motor connector.

Go to step 20.

20

CHECK MAIN FAN MOTOR.
Connect battery positive (+) terminal to termi-
nal No. 1, and negative (

−

) terminal to terminal

No. 4 of main fan motor connector.
Does the main fan rotate?

Rotates.

Repair poor con-
tact in main fan
motor connector.

Replace main fan
motor with a new
one.

21

CHECK POWER SUPPLY TO MAIN FAN RE-
LAY 1.
1) Turn ignition switch to OFF.
2) Remove main fan relay 1 from A/C relay

holder.

3) Measure voltage between main fan relay 1

terminal and chassis ground.

Connector & terminal

(F66) No. 8 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Go to step 22.

Go to step 23.

22

CHECK POWER SUPPLY TO MAIN FAN RE-
LAY 1.
1) Turn ignition switch to ON.
2) Measure voltage between main fan relay 1

terminal and chassis ground.

Connector & terminal

(F66) No. 5 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Go to step 26.

Go to step 25.

23

CHECK 30 A FUSE.
1) Remove 30 A fuse from A/C relay holder.
2) Check condition of fuse.

Is the fuse blown-out?

Fuse is blown out.

Replace fuse.

Go to step 24.

24

CHECK POWER SUPPLY TO A/C RELAY
HOLDER 30 A FUSE TERMINAL.
Measure voltage of harness between A/C relay
holder 30 A fuse terminal and chassis ground.

Connector & terminal

(F27) No. 1 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the specified
value?

10 V

Repair open circuit
in harness
between 30 A fuse
and main fan relay
terminal.

Repair open circuit
in harness
between main fuse
box connector and
30 A fuse terminal.

Step

Value

Yes

No

CO(H6DO)-11

COOLING

RADIATOR MAIN FAN SYSTEM

25

CHECK FUSE.
1) Turn ignition switch to OFF.
2) Remove fuse No. 18 from joint box.
3) Check condition of fuse.

Is the fuse blown-out?

Fuse is blown out.

Replace fuse.

Repair open circuit
in harness
between main fan
relay 1 and ignition
switch.

26

CHECK MAIN FAN RELAY 1.
1) Turn ignition switch to OFF.
2) Remove main fan relay 1.
3) Measure resistance of main fan relay 1.

Terminal

No. 8 — No. 9:

Does the measured value exceed the spec-
ified value?

1 M

Ω

Go to step 27.

Replace main fan
relay 1.

27

CHECK MAIN FAN RELAY.
1) Connect battery to terminals No. 5 and No.

7 of main fan relay 1.

2) Measure resistance of main fan relay 1.

Terminal

No. 8 — No. 9:

Is the measured value less than the speci-
fied value?

1

Ω

Go to step 28.

Replace main fan
relay 1.

28

CHECK HARNESS BETWEEN MAIN FAN
RELAY TERMINAL AND MAIN FAN MOTOR
CONNECTOR.
Measure resistance of harness between main
fan motor connector and main fan relay 1 ter-
minal.

Connector & terminal

(F17) No. 1 — (F66) No. 9:

Is the measured value less than the specified
value?

1

Ω

Go to step 29.

Replace open cir-
cuit in harness
between main fan
motor connector
and main fan relay
1 terminal.

29

CHECK HARNESS BETWEEN MAIN FAN
RELAY 1 AND ECM.
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM.
3) Measure resistance of harness between

main fan relay 1 connector and ECM con-
nector.

Connector & terminal

(F66) No. 7 — (B137) No. 28:

Is the measured value less than the speci-
fied value?

1

Ω

Go to step 30.

Repair open circuit
in harness
between main fan
relay 1 and ECM.

30

CHECK POOR CONTACT.
Check poor contact in connector between main
fan and ECM.
Is there poor contact in connector between
main fan motor and ECM?

There is poor contact.

Repair poor con-
tact connector.

Contact SUBARU
distributor service.

Step

Value

Yes

No

CO(H6DO)-12

COOLING

RADIATOR MAIN FAN SYSTEM

31

CHECK HARNESS BETWEEN MAIN FAN
MOTOR CONNECTOR AND CHASSIS
GROUND.
1) Turn ignition switch to OFF.
2) Disconnect main fan motor connector.
3) Turn A/C switch ON and set the tempera-

ture at the lowest position.

4) Perform checking procedure during coolant

temperature is 98 — 101

°

C (208 — 214

°

F).

5) Measure resistance of harness between

main fan motor connector and chassis
ground.

Connector & terminal

(F17) No. 3 — Chassis ground:

Is the measured value less than the speci-
fied value?

5

Ω

Go to step 32.

Go to step 33.

32

CHECK POOR CONTACT.
Check poor contact in main fan motor connec-
tor.
Is there poor contact in main fan motor con-
nector?

There is poor contact.

Repair poor con-
tact in main fan
motor connector.

Replace main fan
motor with a new
one.

33

CHECK HARNESS BETWEEN MAIN FAN
AND FAN RELAY.
1) Disconnect fan relay connector.
2) Measure resistance of between main fan

motor connector and fan relay connector.

Connector & terminal

(F17) No. 3 — (B253) No. 5:

Is the measured value less than the speci-
fied value?

1

Ω

Go to step 34.

Repair open circuit
between main fan
motor connector
and fan relay con-
nector.

34

CHECK POWER SUPPLY TO FAN RELAY.
1) Turn ignition switch to ON.
2) Measure voltage between fan relay termi-

nal and chassis ground.

Connector & terminal

(B253) No. 1 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Go to step 36.

Go to step 35.

35

CHECK FUSE.
1) Turn ignition switch to OFF.
2) Remove fuse No. 17 from joint box.
3) Check condition of fuse.

Is the fuse blown-out?

Fuse is blown out.

Replace fuse.

Repair open circuit
in harness
between main fan
relay and ignition
switch.

36

CHECK FAN RELAY.
1) Turn ignition switch to OFF.

2) Remove fan relay.
3) Measure resistance of fan relay.

Terminal

No. 4 — No. 5:

Does the measured value exceed the spec-
ified value?

1 M

Ω

Go to step 37.

Replace fan relay.

Step

Value

Yes

No

CO(H6DO)-13

COOLING

RADIATOR MAIN FAN SYSTEM

NOTE:
Inspection by SUBARU distributor service is required, because probable cause is deterioration of multiple
parts.

37

CHECK FAN RELAY.
1) Connect battery to terminals No. 1 and No.

3 of fan relay.

2) Measure resistance of fan relay.

Terminal

No. 4 — No. 5:

Is the measured value less than the speci-
fied value?

1

Ω

Go to step 38.

Replace fan relay.

38

CHECK HARNESS BETWEEN FAN RELAY
TERMINAL AND CHASSIS GROUND.
Measure resistance of harness between fan
relay connector and chassis ground.

Connector & terminal

(B253) No. 4 — Chassis ground:

Is the measured value less than the specified
value?

1

Ω

Go to step 39.

Repair open circuit
in harness
between fan relay
connector and
chassis ground.

39

CHECK HARNESS BETWEEN FAN RELAY
AND ECM.
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM.
3) Measure resistance of harness between

fan relay and ECM connector.

Connector & terminal

(B253) No. 3 — (B137) No. 24:

Is the measured value less than the speci-
fied value?

1

Ω

Go to step 40.

Repair open circuit
in harness
between fan relay
connector and
ECM.

40

CHECK POOR CONTACT.
Check poor contact in connector between fan
relay and ECM.
Is there poor contact in connector between fan
relay and ECM?

There is poor contact.

Repair poor con-
tact connector.

Contact SUBARU
distributor service.

Step

Value

Yes

No