Subaru Legacy III (2000-2003 year). Manual — part 876

AC-40

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

DIAGNOSTICS FOR A/C SYSTEM FAILURE (RHD MODEL)

7

CHECK HARNESS BETWEEN BLOWER
FAN MOTOR RELAY AND A/C CONTROL
MODULE.
1) Disconnect connector from A/C control

module.

2) Measure resistance between blower fan

motor relay and A/C control module har-
ness connector.

Connector & terminal

(B50) No. 3 — (i49) No. 3:

Is the measured value less than the speci-
fied value?

1

Ω

Go to step 8.

Repair harness
between blower
fan motor relay
and A/C control
module.

8

CHECK UNDER AUTO MODE.
1) Connect all of removed relays and discon-

nected connectors.

2) Start the engine and turn the A/C switch to

ON.

3) Select AUTO mode.
4) Check, if blower fan speed changes.

Does change the blower fan speed?

Blower fan speed changes.

Blower fan is OK.

Go to step 9.

9

CHECK FOR POOR CONTACT.
Check, if there is poor contact in A/C control
module connector.
Is there poor contact in the connector?

There is no poor contact.

Replace A/C con-
trol module.

Repair poor con-
tact in connector.

Step

Value

Yes

No

AC-41

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

DIAGNOSTICS FOR A/C SYSTEM FAILURE (RHD MODEL)

D: FRESH/RECIRC DOES NOT CHANGE

TROUBLE SYMPTOM:
FRESH/RECIRC mode door does not change.

AC-42

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

DIAGNOSTICS FOR A/C SYSTEM FAILURE (RHD MODEL)

WIRING DIAGRAM:

Step

Value

Yes

No

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?

Mode selection changes.

Go to step 8.

Go to step 2.

AC-00368

BATTERY

NO. 17

SBF-1

SBF-4

IGNITION

SWITCH

B12

B2

i48

AUTO A/C

CONTROL

MODULE

A:

i49

B:

i52

C

7

3

1

INTAKE DOOR

ACTUATOR

BLOWER MODULE

1

5

8

C

1 2 3 4 5 6 7

i52

1 2

3 4

5 6

7

8 9

10 11 12 13 14

1 2 3 4 5 6 7 8 9 10

11 12 13 14 15 16 17 18 19 20

B:

i49

AC-43

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

DIAGNOSTICS FOR A/C SYSTEM FAILURE (RHD MODEL)

2

CHECK FUSE.
1) Turn ignition switch to OFF.
2) Remove No. 17 fuse in fuse & relay box.
3) Check condition of fuse.

Is the fuse blown-out?

Fuse is not blown.

Go to step 3.

Replace fuse.

3

CHECK POWER SUPPLY VOLTAGE TO
BLOWER MODULE.
1) Remove glove box.
2) Turn ignition switch to ON.
3) Measure voltage between blower module

and chassis ground.

Connector & terminal

(i52) No. 1 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Go to step 4.

Repair harness for
power supply line.

4

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

(i49) No. 12 (+) — Chassis ground (

−−−−

):

Is the measured value less than the speci-
fied value?

1 V

Go to step 5.

Repair harness for
power supply line.

5

CHECK SIGNAL VOLTAGE.
1) Change display to FRESH by pushing

FRESH/RECIRC switch.

2) Measure voltage between A/C control mod-

ule and chassis ground.

Connector & terminal

(i49) No. 2 (+) — Chassis ground (

−−−−

):

Is the measured value less than the speci-
fied value?

1 V

Go to step 6.

Repair harness for
power supply line.

6

CHECK HARNESS CONNECTOR BETWEEN
A/C CONTROL MODULE AND BLOWER
MODULE.
1) Turn ignition switch to OFF.
2) Disconnect connector from A/C control

module and blower module.

3) Measure resistance of harness between A/

C control module and blower module.

Connector & terminal

(i49) No. 12 — (i52) No. 8:

Is the measured value less than the speci-
fied value?

1

Ω

Go to step 7.

Repair harness
between A/C con-
trol module and
blower module.

7

CHECK HARNESS CONNECTOR BETWEEN
A/C CONTROL MODULE AND BLOWER
MODULE.
Measure resistance of harness between A/C
control module and blower module.

Connector & terminal

(i49) No. 2 — (i52) No. 5:

Is the measured value less than the specified
value?

1

Ω

Go to step 8.

Repair harness
between A/C con-
trol module and
blower module.

8

CHECK POOR CONTACT.
Check poor contact in A/C control module con-
nector.
Is there poor contact in connector?

There is no poor contact.

Replace A/C con-
trol module.

Repair connector.

Step

Value

Yes

No