Subaru Legacy 2003 Service Manual page 1768

Step
5 CHECK POWER SUPPLY TO SUB FAN RE-
LAY.
1) Turn ignition switch to OFF.
2) Remove sub fan relay from A/C relay
holder.
3) Measure voltage between sub fan relay ter-
minal and chassis ground.
Connector & terminal
(F28) No. 21 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
6 CHECK POWER SUPPLY TO SUB FAN RE-
LAY.
1) Turn ignition switch to ON.
2) Measure voltage between sub fan relay ter-
minal and chassis ground.
Connector & terminal
(F28) No. 24 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
7 CHECK 20 A FUSE.
1) Remove 20 A fuse from A/C relay holder.
2) Check condition of fuse.
Is the fuse blown-out?
8 CHECK POWER SUPPLY TO A/C RELAY
HOLDER 20 A FUSE TERMINAL.
Measure voltage of harness between A/C relay
holder 20 A fuse terminal and chassis ground.
Connector & terminal
(F27) No. 3 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the specified
value?
9 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?
10 CHECK SUB FAN RELAY.
1) Turn ignition switch to OFF.
2) Measure resistance of sub fan relay.
Terminal
No. 20 — No. 21:
Does the measured value exceed the spec-
ified value?
11 CHECK SUB FAN RELAY.
1) Connect battery to terminals No. 22 and
No. 24 of sub fan relay.
2) Measure resistance of sub fan relay.
Terminal
No. 20 — No. 21:
Is the measured value less than the speci-
fied valve?
RADIATOR SUB FAN SYSTEM
10 V
10 V
Fuse is blown-out.
10 V
Fuse is blown-out.
1 MΩ
1 Ω
CO(H4DOSTC)-13
Value
Go to step 6.
Go to step 10.
Replace fuse.
Repair open circuit
in harness
between 20 A fuse
and sub fan relay
terminal.
Replace fuse.
Go to step 11.
Go to step 12.
COOLING
Yes No
Go to step 7.
Go to step 9.
Go to step 8.
Repair open circuit
in harness
between main fuse
box connector and
20 A fuse terminal.
Repair open circuit
in harness
between sub fan
relay and ignition
switch.
Replace sub fan
relay.
Replace sub fan
relay.