Subaru Impreza 2003, Service Manual

Page: 330 / 3610

CO(H4SO)-8
COOLING
RADIATOR MAIN FAN SYSTEM
B: INSPECTION
DETECTING CONDITION:
• Engine coolant temperature is above 96
°
C (205
°
F).
• Vehicle speed is below 19 km/h (12 MPH).
TROUBLE SYMPTOM:
• Radiator main fan does not rotate under the above conditions.
Step Check Yes No
1 CHECK POWER SUPPLY TO MAIN FAN MO-
TOR.
CAUTION:
Be careful not to overheat the engine during
repair.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from main fan
motor.
3)Start the engine, and warm it up until engine
coolant temperature increases over 96
°
C
(205
°
F).
4)Stop the engine and turn ignition switch to
ON.
5)Measure the voltage between main fan
motor connector and chassis ground.
Connector & terminal
(F17) No. 2 (+) — Chassis ground (
−−−−
):
Is the voltage more than 10 V? Go to step 2. Go to step 5.
2 CHECK GROUND CIRCUIT OF MAIN FAN
MOTOR.
1)Turn the ignition switch to OFF.
2)Measure the resistance between main fan
motor connector and chassis ground.
Connector & terminal
(F17) No. 1 — Chassis ground:
Is the resistance less than 5
Ω
?
Go to step 3. Repair the open
circuit in harness
between main fan
motor connector
and chassis
ground.
3 CHECK POOR CONTACT.
Check poor contact in main fan motor connec-
tor.
Is there poor contact in main
fan motor connector? Repair the poor
contact in main fan
motor connector. Go to step 4.
4 CHECK MAIN FAN MOTOR.
Connect the battery positive (+) terminal to ter-
minal No. 2, and ground (
−
) terminal to termi-
nal No. 1 of main fan motor connector.
Does the main fan rotate? Repair the poor
contact in main fan
motor connector. Replace the main
fan motor with a
new one.
5 CHECK POWER SUPPLY TO MAIN FAN RE-
LAY.
1)Turn the ignition switch to OFF.
2)Remove the main fan relay from A/C relay
holder.
3)Measure the voltage between main fan relay
terminal and chassis ground.
Connector & terminal
(F27) No. 26 (+) — Chassis ground (
−−−−
):
Is the voltage more than 10 V? Go to step 6. Go to step 7.
6 CHECK POWER SUPPLY TO MAIN FAN RE-
LAY.
1)Turn the ignition switch to ON.
2)Measure the voltage between main fan relay
terminal and chassis ground.
Connector & terminal
(F27) No. 28 (+) — Chassis ground (
−−−−
):
Is the voltage more than 10 V? Go to step 10. Go to step 9.
7 CHECK 20 A FUSE.
1)Remove the 20 A fuse from A/C relay holder.
2)Check the condition of fuse.
Is the fuse blown out? Replace the fuse. Go to step 8.