Ground - Subaru Legacy 2003 Service Manual

DIAGNOSTICS FOR A/C SYSTEM FAILURE (LHD MODEL)
HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)
1 CHECK FUSE.
1) Turn ignition switch to OFF.
2) Remove No. 2 fuse in main fuse box.
3) Check condition of fuse.
Is the fuse blown-out?
2 CHECK POWER SUPPLY TO MAGNET
CLUTCH OF A/C COMPRESSOR.
1) Start the engine, and turn A/C switch to
ON.
2) Set the compartment temperature at 18°C
(65°F) (FULL COOL).
3) Measure voltage between magnet clutch
connector and chassis ground.
Connector & terminal
4 CYLINDER MODEL
(F24) No. 1 (+) — Chassis ground ( − − − − ):
6 CYLINDER MODEL
(F82) No. 3 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
3 CHECK SIGNAL VOLTAGE FROM A/C RE-
LAY.
1) Turn ignition switch to ON.
2) Turn A/C switch to ON.
3) Measure voltage to A/C relay and chassis

ground.

Connector & terminal
(F31) No. 10 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
4 CHECK A/C RELAY.
1) Remove A/C relay in main fuse box.
2) Check A/C relay. <Ref. to AC-44, INSPEC-
TION, Relay and Fuse.>
Is the operation of each relay OK?
5 CHECK OPERATION OF MAIN FAN MOTOR.
1) Start the engine.
2) Turn A/C switch to ON.
3) Check operation of main fan motor.
Does the radiator main fan operate?
Step Value
No fuse blown out.
10 V
10 V
Relay operates normally.
Main fan motor operates.
AC-26
Yes
Replace fuse. Go to step 2.
Go to step 3. Repair harness for
power supply line
of the A/C com-
pressor.
Go to step 4. Repair harness for
power supply line.
Go to step 5. Replace A/C relay.
Go to step 10. Go to step 6.
No