1996 SUBARU LEGACY relay

1. Engine Cooling System
Trouble Possible cause Corrective action
Over-heatinga. Insufficient engine coolantReplenish engine coolant, inspect for leakage, and
repair.
b. Loose timing belt Repair or replace timing belt tensioner.
c. Oil on drive belt Replace.
d. Malfunction of thermostat Replace.
e. Malfunction of engine coolant pump Replace.
f. Clogged engine coolant passage Clean.
g. Improper ignition timingInspect and repair ignition control system.

h. Clogged or leaking radiator Clean or repair, or replace.
i. Improper engine oil in engine coolant Replace engine coolant.
j. Air/fuel mixture ratio too leanInspect and repair fuel injection system.

k. Excessive back pressure in exhaust system Clean or replace.
l. Insufficient clearance between piston and cylinder Adjust or replace.
m. Slipping clutch Repair or replace.
n. Dragging brake Adjust.
o. Improper transmission oil Replace.
p. Defective thermostat Replace.
q. Malfunction of electric fanInspect radiator fan relay, engine coolant temperature
sensor or radiator motor and replace there.
Over-coolinga. Atmospheric temperature extremely low Partly cover radiator front area.
b. Defective thermostat Replace.
Engine coolant
leaks.a. Loosened or damaged connecting units on hoses Repair or replace.
b. Leakage from engine coolant pump Replace.
c. Leakage from engine coolant pipe Repair or replace.
d. Leakage around cylinder head gasket Retighten cylinder head bolts or replace gasket.
e. Damaged or cracked cylinder head and crankcase Repair or replace.
f. Damaged or cracked thermostat case Repair or replace.
g. Leakage from radiator Repair or replace.
Noisea. Defective drive belt Replace.
b. Defective radiator fan Replace.
c. Defective engine coolant pump bearing Replace engine coolant pump.
d. Defective engine coolant pump mechanical seal Replace engine coolant pump.
20
2-5DIAGNOSTICS
1. Engine Cooling System

A: OPERATION (WITHOUT A/C MODEL)
CONDITION:
Engine coolant temperature is above 95°C (203°F).
TROUBLE SYMPTOM:
Radiator main fan does not operate under the above
condition.
1. Check fuse and power supply.
OK
Not OK
Melted fuse,repair the shorted part of the circuit
,replace fuse.
2. Check harness connector between fuse and
relay box, and A/C relay holder.
OK
Not OK
Repair or replace wiring harness.
3. Check A/C relay holder.
OK
Not OK
Repair or replace A/C relay holder.
4. Check harness connector between A/C relay
holder and main fan motor.
OK
Not OK
Repair or replace wiring harness.
5. Check ground circuit of main fan motor.
OK
Not OK
Repair or replace wiring harness.
6. Check main fan motor.
OK
Not OK
Replace main fan motor.
Refer to 2-7 On-Board Diagnostics II System.
B2M0427A
1. CHECK FUSE AND POWER SUPPLY.
1) Check fuse No. 13.
2) Turn ignition switch to ACC.
3) Measure voltage between fuse and relay box, and body.
Connector & terminal / Specified voltage:
(F40) No. 3—Body / 10 V, or more






22
2-5DIAGNOSTICS
2. Radiator Main Fan

B2M0325A
2. CHECK HARNESS CONNECTOR BETWEEN FUSE
AND RELAY BOX, AND A/C RELAY HOLDER.
1) Turn ignition switch to OFF.
2) Disconnect connectors from fuse and relay box, and
A/C relay holder.
3) Measure resistance of harness connector between fuse
and relay box, and A/C relay holder.
Connector & terminal / Specified resistance:
(F40) No. 3—(F29) No. 2 / 10Ω, max.
B2M0428A
3. CHECK A/C RELAY HOLDER.
1) Disconnect connector from A/C relay holder.
2) Measure resistance between terminals of A/C relay
holder.
Connector & terminal / Specified resistance:
(F29) No. 2—(F28) No. 4 / 10Ω, max.
(F29) No. 2—(F30) No. 4 / 10Ω, max.
B2M0366A
4. CHECK HARNESS CONNECTOR BETWEEN A/C
RELAY HOLDER AND MAIN FAN MOTOR.
1) Disconnect connectors from A/C relay holder and main
fan motor.
2) Measure resistance of harness connector between A/C
relay holder and main fan motor.
Connector & terminal / Specified resistance:
(F28) No. 4—(F17) No. 2 / 10Ω, max.
(F30) No. 4—(F17) No. 3 / 10Ω, max.
B2M0367A
5. CHECK GROUND CIRCUIT OF MAIN FAN MOTOR.
Measure resistance between main fan motor connector
and body.
Connector & terminal / Specified resistance:
(F17) No. 1—Body / 10Ω, max.
B2M0368A
6. CHECK MAIN FAN MOTOR.
1) Disconnect connector from main fan motor.
2) Connect battery positive (+) terminal to terminals No. 2
and No. 3, and connect terminal No. 1 to ground. Ensure
that fan rotates.
23
2-5DIAGNOSTICS
2. Radiator Main Fan

B: LO MODE OPERATION (WITH A/C MODEL)
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.
1. Check power supply to main fan relay-1.
OK
Not OK
Melted fuse (in A/C relay holder),repair the
shorted part of the circuit,replace fuse.
2. Check main fan relay-1.
OK
Not OK
Replace main fan relay-1.
3. Check harness connector between main fan
relay-1 and main fan motor.
OK
Not OK
Repair or replace wiring harness.
4. Check ground circuit of main fan motor.
OK
Not OK
Repair or replace wiring harness.
5. Check main fan motor.
OK
Not OK
Replace main fan motor.
Refer to 2-7 On-Board Diagnostics II System.





24
2-5DIAGNOSTICS
2. Radiator Main Fan

B2M0369A
1. CHECK POWER SUPPLY TO MAIN FAN RELAY-1.
1) Turn ignition switch to OFF.
2) Disconnect connector from A/C relay holder.
3) Measure voltage between A/C relay holder connector
and body.
Connector & terminal / Specified voltage:
(F28) No. 2—Body / 10 V, or more
(F28) No. 1—Body / 1 V, max.
4) Turn ignition switch to ON.
5) Measure voltage between A/C relay holder connector
and body.
Connector & terminal / Specified voltage:
(F28) No. 1—Body / 10 V, or more
B2M0370A
2. CHECK MAIN FAN RELAY-1.
1) Turn ignition switch to OFF.
2) Remove main fan relay-1 from A/C relay holder.
3) Check continuity between terminals (indicated in table
below) when terminal (1) is connected to battery and ter-
minal (3) is grounded.
When current flows.Between terminals (2)
and (4)Continuity exists.
When current does not
flow.Between terminals (2)
and (4)Continuity does not
exist.
Between terminals (1)
and (3)Continuity exists.
B2M0371A
3. CHECK HARNESS CONNECTOR BETWEEN MAIN
FAN RELAY-1 AND MAIN FAN MOTOR.
1) Disconnect connectors from main fan relay-1 and main
fan motor.
2) Measure resistance of harness connector between
main fan relay-1 and main fan motor.
Connector & terminal / Specified resistance:
(F28) No. 4—(F17) No.2 / 10Ω, max.
25
2-5DIAGNOSTICS
2. Radiator Main Fan

C: HI MODE OPERATION (WITH A/C MODEL)
CONDITION:
Condition (1) :
Engine coolant temperature is below 89°C (192°F).
A/C switch is turned ON.
Vehicle speed is over 20 km/h (12 MPH).
Condition (2) :
Engine coolant temperature is above 95°C (203°F).
A/C switch is turned OFF.
Vehicle speed is over 20 km/h (12 MPH).
Condition (3) :
Engine coolant temperature is above 95°C (203°F).
A/C switch is turned ON.
TROUBLE SYMPTOM:
Radiator main fan does not rotate at HI speed under
conditions (1), (2) and (3) above.
1. Check operation of main fan motor LO mode.
OK
Not OK
Check LO mode operation.
2. Check power supply to main fan relay-2.
OK
Not OK
Melted fuse (in A/C relay holder),repair the
shorted part of the circuit,replace fuse.
3. Check main fan relay-2.
OK
Not OK
Replace main fan relay-2.
4. Check harness connector between main fan
relay-2 and main fan motor.
OK
Not OK
Repair or replace wiring harness.
5. Check ground circuit of main fan motor.
OK
Not OK
Repair or replace wiring harness.
6. Check main fan motor.
OK
Not OK
Replace main fan motor.
Refer to 2-7 On-Board Diagnostics II System.






27
2-5DIAGNOSTICS
2. Radiator Main Fan

1. CHECK OPERATION OF MAIN FAN MOTOR LO
MODE.
Check that radiator main fan rotates at LO speed under
each condition described under LO mode operation. to 2-5 [K2B0].>
B2M0374A
2. CHECK POWER SUPPLY TO MAIN FAN RELAY-2.
1) Turn ignition switch to OFF.
2) Disconnect connector from A/C relay holder.
3) Measure voltage between A/C relay holder connector
and body.
Connector & terminal / Specified voltage:
(F30) No. 2—Body / 10 V, or more
(F30) No. 1—Body / 1 V, max.
4) Turn ignition switch to ON.
5) Measure voltage between A/C relay holder connector
and body.
Connector & terminal / Specified voltage:
(F30) No. 1—Body / 10 V, or more
B2M0370A
3. CHECK MAIN FAN RELAY-2.
1) Turn ignition switch to OFF.
2) Remove main fan relay-2 from A/C relay holder.
3) Check continuity between terminals (indicated in table
below) when terminal (1) is connected to battery and ter-
minal (3) is grounded.
When current flows.Between terminals (2)
and (4)Continuity exists.
When current does not
flow.Between terminals (2)
and (4)Continuity does not
exist.
Between terminals (1)
and (3)Continuity exists.
28
2-5DIAGNOSTICS
2. Radiator Main Fan

B2M0375A
4. CHECK HARNESS CONNECTOR BETWEEN MAIN
FAN RELAY-2 AND MAIN FAN MOTOR.
1) Disconnect connectors from main fan relay-2 and main
fan motor.
2) Measure resistance of harness connector between
main fan relay-2 and main fan motor.
Connector & terminal / Specified resistance:
(F30) No. 4—(F17) No. 3 / 10Ω, max.
B2M0367A
5. CHECK GROUND CIRCUIT OF MAIN FAN MOTOR.
Measure resistance between main fan motor connector
and body.
Connector & terminal / Specified resistance:
(F17) No. 1—Body / 10Ω, max.
B2M0368A
6. CHECK MAIN FAN MOTOR.
1) Disconnect connector from main fan motor.
2) Connect battery positive (+) terminal to terminals No. 2
and No. 3, and connect terminal No. 1 to ground. Ensure
that fan rotates at HI speed.
29
2-5DIAGNOSTICS
2. Radiator Main Fan