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Home >> Subaru >> 1998 >> Legacy Outback AWD F4-2.5L DOHC >> Repair and Diagnosis >> Engine, Cooling and Exhaust >> Cooling System >> Radiator Cooling Fan >> Radiator Cooling Fan Motor >> Testing and Inspection >> Radiator Main Fan LO Mode with AC

Radiator Main Fan LO Mode with AC

B: LO MODE OPERATION (WITH A/C MODEL)
DETECTING CONDITION:
Condition (1):
- Engine coolant temperature is below 89°C (192°F).
- A/C switch is turned ON.
- Vehicle speed is below 10 km/h (6 MPH).
Condition (2):
- Engine coolant temperature is above 95°C (203° F).
- A/C switch is turned OFF.
- Vehicle speed is below 10 km/h (6 MPH).

TROUBLE SYMPTOM:
- Radiator main fan does not rotate at LO speed under conditions (1) and (2) above.

1B1 : CHECK POWER SUPPLY TO MAIN FAN MOTOR.

CAUTION: Be careful not to overheat engine during repair.

1) Turn ignition switch to OFF.
2) Disconnect connector from main fan motor.
3) Start the engine, and warm-up it until engine coolant temperature increases over 95°C (203°F).
4) Stop the engine and turn ignition switch to ON.
5) Turn A/C switch to OFF.
6) Measure voltage between main fan motor connector and chassis ground.
Connector & terminal
(F17) No.2 (+) Chassis ground (-):






(CHECK) Is voltage more than 10 V?
(YES) Go to step 1B2.
(NO) Go to step 1B5.

1B2: CHECK GROUND CIRCUIT OF MAIN FAN MOTOR.
1) Turn ignition switch to OFF.
2) Measure resistance between main fan motor connector and chassis ground.
Connector & terminal
(F17) No.1 - Chassis ground:






(CHECK) Is resistance less than 5 ohms?
(YES) Go to step 1B3.
(NO) Repair open circuit in harness between main fan motor connector and chassis ground.

1B3: CHECK POOR CONTACT.
Check poor contact in main fan motor connector.
(CHECK) Is there poor contact in main fan motor connector?
(YES) Repair poor contact in main fan motor connector.
(NO) Go to step 1B4.

1B4: CHECK MAIN FAN MOTOR.
Connect battery positive (+) terminal to terminals No.2 of main fan motor connector, and negative (-) terminal to terminal No.1.






(CHECK) Does the main fan rotate at LO speed?
(YES) Repair poor contact in main fan motor connector.
(NO) Replace main fan motor with a new one.

1B5: CHECK POWER SUPPLY TO MAIN FAN RELAY-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
(F28) No.2 (+) Chassis ground (-):






(CHECK) Is voltage more than 10 V?
(YES) Go to step 1B6.
(NO) Go to step 1B7.
1) Turn ignition switch to ON.
2) Measure voltage between main fan relay-1 terminal and chassis ground.
Connector & terminal
(F28) No.1 (+) Chassis ground (-):






(CHECK) Is voltage more than 10 V?
(YES) Go to step 1B17.
(NO
1) Turn ignition switch to OFF.
2) Remove 20 A fuse from A/C relay holder.
3) Check condition of fuse.






(CHECK) Is the fuse blown-out?
(YES) Replace fuse.
(NO) Go to step 1B8.

1B8: CHECK HARNESS CONNECTOR BETWEEN MAIN FUSE BOX AND A/C RELAY HOLDER 20 A FUSE.
1) Turn ignition switch to OFF.
2) Disconnect connector from main fuse box.
3) Disconnect connectors (F25) and (F26) from generator.
4) On LHD model, disconnect connector (F34) from SBF holder.
5) Measure resistance of harness between main fuse box connector and A/C relay holder 20 A fuse terminal.
Connector & terminal (F38) No.2 - (F27) No.1:






(CHECK Is resistance less than 1 ohm?
(YES) Go to step 1B9.
(NO) Repair open circuit in harness between main fuse box connector and 20 A fuse terminal.

1B9: CHECK POOR CONTACT.
Check poor contact in main fuse box connector
(CHECK) Is there poor contact in main fuse box connector?
(YES) Repair poor contact in main fuse box connector.
(NO)Go to step 1B1O.

1B1O: CHECK POOR CONTACT.
Check poor contact in A/C relay holder 20A fuse connector.
(CHECK) Is there poor contact in A/C relay holder 20 A fuse connector?
(YES) Repair poor contact in 20 A fuse connector.
(NO) Go to step 1B11

1B11: CHECK HARNESS CONNECTOR BETWEEN 20 A FUSE AND MAIN FAN RELAY-1 IN A/C RELAY HOLDER.
Measure resistance of harness between 20 A fuse and main fan relay-1 terminal.
Connector & terminal (F27) No.2 - (F28) No.2:






(CHECK) Is resistance less than 1 ohm?
(YES) Repair poor contact in main fan relay-1 connector.
(NO) Repair open circuit in harness between 20 A fuse and main fan relay-1 connector.

1B12: CHECK 1OA FUSE.


1) Turn ignition switch to OFF.
2) Remove 10 A fuse from A/C relay holder.
3) Check condition of fuse.






(CHECK) Is the fuse blown-out?
(YES) Replace fuse.
(NO) Go to step 1B13.

1B13: CHECK HARNESS CONNECTOR BETWEEN IGNITION SWITCH AND A/C RELAY HOLDER 10 A FUSE.
1) Turn ignition switch to OFF.
2) Disconnect connector from ignition switch.
3) Disconnect connector (i5) from fuse and relay box.
4) Measure resistance of harness between ignition switch connector and A/C relay holder 10 A fuse terminal.
Connector & terminal (B72) No.2 - (F27) No.3:






(CHECK) Is resistance less than 1 ohm?
(YES) Go to step 1B14.
(NO) Repair harness and connector

NOTE: In this case, repair the following:
- Open circuit in harness between ignition switch connector and 10 A fuse terminal.
- Poor contact in coupling connector (B61).

1B14: CHECK POOR CONTACT.
Check poor contact in ignition switch connector.
(CHECK) Is there poor contact in ignition switch connector?
(YES) Repair poor contact in ignition switch connector.
(NO) Go to step 1B15.

1B15: CHECK POOR CONTACT.
Check poor contact in A/C relay holder 1OA fuse connector.
(CHECK) Is there poor contact in A/C relay holder 10 A fuse connector?
(YES) Repair poor contact in 1OA fuse connector.
(NO) Go to step 1B16.

1B16: CHECK HARNESS CONNECTOR BETWEEN 10 A FUSE AND MAIN FAN RELAY-1 IN A/C RELAY HOLDER.
Measure resistance of harness between 10 A fuse and main fan relay-1 terminal.
Connector & terminal (F27) No. 4 - (F28) No.1:






(CHECK) Is resistance less than 1 ohm?
(YES) Repair poor contact in main fan relay-1 connector.
(NO) Repair open circuit in harness between 10 A fuse and main fan relay-1 connector.

B17: CHECK MAIN FAN RELAY-1.
1) Turn ignition switch to OFF.
2) Check continuity between main fan relay-1 terminals.






(CHECK) Does continuity exist between terminals No. 2 and No.4?
(YES) Replace main fan relay-1.
(NO) Go to step 1B18.

1B18: CHECK MAIN FAN RELAY-1.
1) Connect battery to terminals No.1 and No.3 of main fan relay-1.
2) Check continuity between main fan relay-1 terminals.






(CHECK) Does continuity exist between terminals No. 2 and No.4?
(YES) Go to step 1B19.
(NO) Replace main fan relay-1.

1B19: CHECK HARNESS CONNECTOR BETWEEN MAIN FAN RELAY-1 AND MAIN FAN MOTOR.
Measure resistance of harness between main fan motor connector and main fan relay-1 terminal.

Connector & terminal (F17) No.2 - (F28) No.4:






(CHECK) Is resistance less than 1 ohm?
(YES) Go to step 1B20.
(NO) Repair open circuit in harness between main fan motor and main fan relay-1 connector.

1B20: CHECK POOR CONTACT.
Check poor contact in main fan relay-1 connector.
(CHECK) Is there poor contact in main fan relay-1 connector?
(YE) Repair poor contact in main fan relay-1 connector.
(NO) Go to step 1B21.

1B21: CHECK POOR CONTACT.
Check poor contact in main fan motor connector.
(CHECK) Is there poor contact in main fan motor connector?
(YES) Repair poor contact in main fan motor connector.
(NO) Refer to"On-Board Diagnostics II System" diagnostics procedure.
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