Subaru Legacy 2003 Service Manual page 3496

DIAGNOSTICS FOR A/C SYSTEM FAILURE (LHD MODEL)
Step
1 CHECK FUSE.
1) Remove No. 1, No. 2 and No. 17 fuses in
fuse & relay box.
2) Check condition of fuses.
Are any of the fuses blown-out?
2 CHECK POWER SUPPLY TO BLOWER FAN
MOTOR.
1) Turn ignition switch to ON.
2) Turn blower switch to ON.
3) Measure voltage between blower fan motor
and chassis ground.
Connector & terminal
(B87) No. 1 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
3 CHECK BLOWER FAN MOTOR RELAY.
1) Turn ignition switch to OFF.
2) Remove blower fan motor relay.
3) Connect terminals as follows:
Positive terminal (+) of battery to terminal
No. 1 of blower fan motor relay
Negative terminal (−) of battery to terminal
No. 3 of blower fan motor relay
4) Measure resistance between No. 2 and No.
4 terminals.
Terminals
No. 2 — No. 4:
Is the measured value less than the speci-
fied value?
4 CHECK BLOWER FAN MOTOR.
1) Disconnect connector from blower fan
motor.
2) Connect terminals as follows:
Positive terminal (+) of battery to terminal
No. 1 of blower fan motor relay
Negative terminal (−) of battery to terminal
No. 2 of blower fan motor relay
3) Make sure that blower fan motor is oper-
ated.
Does the blower fan motor operate?
5 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
Fuse is not blown-out.
10 V
1 Ω
Blower fan motor operates.
There no poor contact.
AC-23
Yes
Go to step 2. Replace fuse.
Go to step 3. Repair harness for
blower fan motor
power supply line.
Go to step 4. Replace blower
fan motor relay.
Go to step 5. Replace blower
fan motor.
Replace A/C con- Repair connector.
trol module.
No