Subaru Legacy 2003 Service Manual page 3504

DIAGNOSTICS FOR A/C SYSTEM FAILURE (LHD MODEL)
Step
1 CHECK SWITCH OPERATION.
Make sure that the mode selection on display
is changed when pushing the "FRESH/
RECIRC" switch.
Does the mode selection change?
2 CHECK FUSE.
1) Remove No. 17 fuse in fuse & relay box.
2) Check condition of fuse.
Is the fuse blown-out?
3 CHECK SIGNAL VOLTAGE.
1) Change display to RECIRC by pushing
FRESH/RECIRC switch.
2) Measure voltage between A/C control mod-
ule and chassis ground.
Connector & terminal
(i48) No. 15 (+) — Chassis ground ( − − − − ):
Is the measured value less than the speci-
fied value?
4 CHECK SIGNAL VOLTAGE.
1) Change display to FRESH with pushing
FRESH/RECIRC switch.
2) Measure voltage between A/C control mod-
ule and chassis ground.
Connector & terminal
(i48) No. 7 (+) — Chassis ground ( − − − − ):
Is the measured value less than the speci-
fied value?
5 CHECK HARNESS CONNECTOR BETWEEN
A/C CONTROL MODULE AND INTAKE
DOOR ACTUATOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from A/C control
module and intake door motor.
3) Measure resistance of harness between A/
C control module and intake door actuator.
Connector & terminal
(i48) No. 15 — (B91) No. 1:
Is the measured value less than the speci-
fied value?
6 CHECK HARNESS CONNECTOR BETWEEN
A/C CONTROL MODULE AND INTAKE
DOOR ACTUATOR.
Measure resistance of harness between A/C
control module and intake door actuator.
Connector & terminal
(i48) No. 7 — (B91) No. 2:
Is the measured value less than the specified
value?
7 CHECK POOR CONTACT.
Check poor contact in A/C control module con-
nector.
Is there poor contact in connector?
HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)
Value
Mode selection changes.
Fuse is not blown-out.
1 V
1 V
1 Ω
1 Ω
There is no poor contact.
AC-31
Yes
Go to step 7. Go to step 2.
Go to step 3. Replace fuse.
Go to step 4. Repair short circuit
in harness
between A/C con-
trol module and
intake door actua-
tor.
Go to step 5. Repair short circuit
in harness
between A/C con-
trol module and
intake door actua-
tor.
Go to step 6. Repair open circuit
in harness
between A/C con-
trol module and
intake door actua-
tor.
Go to step 7. Repair open circuit
in harness
between A/C con-
trol module and
intake door actua-
tor.
Replace A/C con- Repair connector.
trol module.
No