Subaru Legacy (2005 year). Service manual — part 875

AC(diag)-17

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

Diagnostics for A/C System Malfunction

9

CHECK AUTO A/C CONTROL MODULE
GROUND CIRCUIT.
Measure the resistance in harness between
auto A/C control module and chassis ground.

Connector & terminal

(B282) No. 14, No. 16 — Chassis ground:

Is the resistance less than 5
Ω?

Go to step 10.

Repair the har-
ness for ground
line.

10

CHECK COMMUNICATION CIRCUIT.
Measure the resistance in harness between A/
C control panel and auto A/C control module.

Connector & terminal

(i88) No. 3 — (B283) No. 16:
(i88) No. 7 — (B283) No. 15:

Is the resistance less than1

Ω? Go to step 11.

Repair the har-
ness.

11

CHECK POOR CONTACT.
Check poor contact in auto A/C control module
connector.

Is there poor contact in con-
nector?

Repair the con-
nector.

Replace the auto
A/C control mod-
ule.

Step

Check

Yes

No

AC(diag)-18

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

Diagnostics for A/C System Malfunction

B: BLOWER FAN DOES NOT ROTATE.

TROUBLE SYMPTOM:
• Blower motor does not rotate.
• Blower motor does not rotate in “HI”.
WIRING DIAGRAM:

B2

B3

B13

B225

B87

B86

BATTERY

F/B No. 27

F/B No. 28

F/B No. 22

SBF-3

MAIN SBF

SBF-6

B283

1 2 3 4 5 6 7 8 9 10

11 12 13 14 15 16 17 18 19 20

B:

2
4
1

22
24
23
21

2
1

BLOWER MOTOR

BLOWER MOTOR
RELAY

IGNITION

SWITCH

B87

B86

3 4

1 2

B283

B:

AUTO A/C CONTROL MODULE

AC-01249

E

M

3

1 2

9

10

1

2

3

4

5

6

7

8

11 12

14

15 16

13

18

19 20

17

22

23 24

21

38

39 40

37

34

35 36

33

30

31 32

29

26

27 28

25

B225

POWER
TRANSISTOR

AC(diag)-19

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

Diagnostics for A/C System Malfunction

Step

Check

Yes

No

1

CHECK FUSE.
1) Remove the fuse No. 22, 27 and 28 from
fuse & relay box.
2) Check the condition of fuse.

Is any fuse blown-out?

Replace the fuse.

Go to step 2.

2

CHECK POWER SUPPLY FOR BLOWER
MOTOR.
1) Turn the ignition switch to ON.
2) Turn the blower switch to ON.
3) Measure the voltage between blower motor
and chassis ground.

Connector & terminal

(B87) No. 2 (+) — Chassis ground (

−

):

Is the voltage more than 10 V? Go to step 3.

Repair the open
circuit of blower
motor power sup-
ply line harness.

3

CHECK BLOWER MOTOR RELAY.
1) Turn the ignition switch to OFF.
2) Remove the blower motor relay.
3) Connect the battery positive (+) terminal to
terminal No. 24 of blower motor relay, and neg-
ative (

−) terminal to terminal No. 23.

4) Measure the resistance between terminals
No. 21 and 22.

Terminals

No. 21 — No. 22:

Is the resistance less than 1
Ω?

Go to step 4.

Replace the
blower motor relay.

4

CHECK BLOWER MOTOR.
1) Disconnect the connector from blower
motor.
2) Connect the battery positive (+) terminal to
terminal No. 2 of blower motor connector, and
negative (

−) terminal to terminal No. 1.

3) Make sure the blower motor runs.

Does the blower motor run?

Go to step 5.

Replace the
blower motor.

5

CHECK POOR CONTACT.
Check poor contact in auto A/C control module
connector.

Is there poor contact in con-
nector?

Repair the con-
nector.

Replace the auto
A/C control mod-
ule.

AC(diag)-20

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

Diagnostics for A/C System Malfunction

C: COMPARTMENT TEMPERATURE DOES NOT CHANGE, OR A/C SYSTEM

DOES NOT RESPOND PROMPTLY.

WIRING DIAGRAM:

AC-01250

MAIN SBF

SBF-6

F/B No.22

B360

F109

B143

B:

F37

A:

F35

C:

1

9

ND

HU

F24

1

2

B361

F108

B135

B136

B137

B:

C:

D:

ECM

B283

B:

B282

A:

B282

B10

F24

A:

B283

B:

B137

D:

B143

B360

F109

F108

B:

F37

A:

F35

F27

C:

B143

B:

F37

A:

F35

C:

F27

B10

14

9

28

30

29

31

E

E

C3

C7

A4

B13

2

4

1

3

HU

B20

C8

B33 B35

ND

D17

C30

A10

B6

E

A13

B20

C12

1 2 3 4 5 6 7 8
9 10 11 12 13 14 15 16

1 2

1 2 3 4

5 6 7 8 9

10 11 12 13 14

15 16 17 18 19 20

1 2

3 4 5

6 7 8 9 10 11 12

2

3

1

4

2 3 4

5 6 7 8 9

11 12 13 14

17 18 19 20

1

10

15 16

B361

1 2 3

4 5 6

7 8 9 10 11 12 13 14

1 2 3

8

9 10

4

11 12 13 14 15 16

5 6 7

17 18

1 2 3
8 9 10

4

11 12 13 14 15 16

5 6 7

1
2
3

6

7

4 5

13
14
15

11

30
31

16 17

8 9 10

12

26
27

18

19

29 28

22
23

20 21

24 25

3 4

1 2

8 9 10 11

12 13 14 15 16 17 18 19 20 21 22 23 24

5

6 7

1 2 3 4 5 6 7 8 9 10

11 12 13 14 15 16 17 18 19 20

1

2

7

8 9

5

6

3

4

10 11 12

19 20 21

29

30 31

13 14 15 16 17

27

28

18

22 23

24 25

26

B135

B:

1

2

7

8 9

5

6

3

4

10 11 12

19

20 21

29 30 31

13 14 15 16 17

27

28

18

22 23

24 25

26

32 33

34 35

B136

C:

1

2

8 9

5

6

3

4

10 11 12

19 20 21

29 30

31

13 14 15 16

17

27

28

18

22 23 24 25 26

7

32 33 34 35

AUTO A/C

CONTROL MODULE

: 2.0 L TURBO MODEL, 3.0 L MODEL
AND 2.5 L EC, K4, EK MODEL

: 2.0 L NON-TURBO MODEL
AND 2.5 L KS, KA MODEL

A/C RELAY

BATTERY

IGNITION SWITCH

THROUGH JOINT
CONNECTOR

THROUGH JOINT
CONNECTOR

PRESSURE
SWITCH

MAIN FUSE BOX

MAIN FUSE BOX

MAGNET
CLUTCH