Subaru Legacy (2005 year). Manual - part 880

AC(diag)-37

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

Diagnostic Procedure for Sensors

D: SUNLOAD SENSOR

TROUBLE SYMPTOM:
• Sensor identifies that sunlight is at maximum. Then, A/C system is controlled to COOL side.
• Sensor identifies that sunlight is at minimum. Then, A/C system is controlled to HOT side.

NOTE:
When the sunload sensor check is conducted indoors or in the shade, open circuit might be indicated. Always
check the sunload sensor at the place where the sun shines directly on it.
WIRING DIAGRAM:

AC-00832

A: B282

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

i51

A: B282

A8

A6

2

1

i3

B38

i51

1 2

AUTO A/C 

CONTROL MODULE

3

2

1 2 3 4

5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20

B38

SUNLOAD

SENSOR

AC(diag)-38

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

Diagnostic Procedure for Sensors

Step

Check

Yes

No

1

CHECK POWER SUPPLY VOLTAGE FOR 
SUNLOAD SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from sunload 
sensor.
3) Turn the ignition switch to ON.
4) Measure the power supply voltage for sun-
load sensor.

Connector & terminal

(i51) No. 1 (+) — No. 2 (

−

):

Is the voltage approx. 5 V?

Go to step 4.

Go to step 2.

2

CHECK HARNESS CONNECTOR BETWEEN 
AUTO A/C CONTROL MODULE AND SUN-
LOAD SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from auto A/C 
control module.
3) Measure the resistance in harness 
between auto A/C control module and sunload 
sensor.

Connector & terminal

(i51) No. 2 — (B282) No. 6:

Is the resistance less than 1 
Ω?

Go to step 3.

Repair the har-
ness between auto 
A/C control mod-
ule and sunload 
sensor.

3

CHECK HARNESS CONNECTOR BETWEEN 
AUTO A/C CONTROL MODULE AND SUN-
LOAD SENSOR.
Measure the resistance in harness between 
auto A/C control module and sunload sensor.

Connector & terminal

(i51) No. 1 — (B282) No. 8:

Is the resistance less than 1 
Ω?

Go to step 4.

Repair the har-
ness between auto 
A/C control mod-
ule and sunload 
sensor.

4

CHECK INPUT VOLTAGE FOR AUTO A/C 
CONTROL MODULE.
1) Connect the connectors of sunload sensor 
and auto A/C control module.
2) Turn the ignition switch to ON.
3) Measure the voltage between connector 
terminals of auto A/C control module.

Connector & terminal

(B282) No. 8 (+) — (B282) No. 6 (

−

):

Is the voltage approx. 2.5 V?

Go to step 5.

Replace the sun-
load sensor.

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)-39

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

Diagnostic Procedure for Sensors

E: A/C LOCK SENSOR

• H6  model
WIRING DIAGRAM:

B283

1 2 3 4

5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20

F37

A:

5

6

7

8

2

1

9

4

3

10

24

22 23

25

11 12 13 14 15

26 27

28

16 17 18 19

20 21

29 30 31

32 33

34 35

B135

B:

F115

1 2

B137

8

5

6

10 11 12 13 14 15

7

2

1

3

4

16

30

19 20

22
28 29

9

17

18

25

21

23

24

31

26 27

D:

B283

1 2 3 4 5 6 7 8 9 10

11 12 13 14 15 16 17 18 19 20

B143

1 2 3 4

5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20

B:

E

36

B21

E2

B122

*

*

*

B1

B135

B23

D17

ECM

B137

B:

D:

6

A20

A18

A16

F37

A:

B143

B:

B10

2

1

F115

B12

B14

AC-01703

AUTO A/C CONTROL MODULE

MAIN

FUSE

BOX

(M/B)

A/C
LOCK
SENSOR

JOINT

CONNECTOR

B

*

: TERMINAL No. RANDOM
  ARRANGEMENT

AC(diag)-40

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

Diagnostic Procedure for Sensors

Step

Check

Yes

No

1

CHECK A/C LOCK SENSOR SIGNAL.
1) Turn the ignition switch to OFF.
2) Connect the Subaru Select Monitor to data 
link connector.
3) Start the engine and turn A/C to ON.
4) Read the data of A/C lock signal using Sub-
aru Select Monitor.

NOTE:

• Subaru Select Monitor
For detailed operation procedure, refer to 
“READ CURRENT DATA FOR ENGINE”. <Ref. 
to EN(H6DO)(diag)-27, READ CURRENT 
DATA FOR ENGINE. (NORMAL MODE), 
OPERATION, Subaru Select Monitor.>

Is the A/C lock signal ON?

Go to step 4.

Go to step 2.

2

CHECK A/C LOCK SENSOR SIGNAL.
1) Start the engine and turn A/C to ON.
2) Measure the voltage between auto A/C 
control module connector and chassis ground.

Connector & terminal

(B283) No. 6 (+) — Chassis ground (

−

):

Is the voltage 7 — 14 V?

Replace the auto 
A/C control mod-
ule.

Go to step 3.

3

CHECK OUTPUT OF ECM.
Measure the voltage between ECM and chas-
sis ground.

Connector & terminal

(D137) No. 17 (+) — Chassis ground (

−

):

Is the voltage 7 — 14 V?

Repair the har-
ness between 
ECM and auto A/C 
control module.

Replace the ECM.

4

CHECK A/C LOCK SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the ECM connector.
3) Measure the resistance between ECM con-
nector and chassis ground.

Connector & terminal

(B135) No. 23 — Chassis ground:

Is the resistance 240 — 290 
Ω?

Replace the ECM. Go to step 5.

5

CHECK A/C LOCK SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the main fuse box connector.
3) Measure the resistance between main fuse 
box terminals.

Connector & terminal

(F37) No. 16 — No. 18:

Is the resistance 240 — 290 
Ω?

Go to step 7.

Go to step 6.

6

CHECK A/C LOCK SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the A/C lock sensor connector.
3) Measure the resistance between A/C lock 
sensor terminals.

Connector & terminal

(F115) No. 1 — No. 2:

Is the resistance 240 — 290 
Ω?

Repair or replace 
the harness 
between A/C lock 
sensor and main 
fuse box.

Replace the A/C 
compressor 
assembly. (A/C 
lock switch is 
faulty.)

7

CHECK MAIN FUSE BOX.
1) Turn the ignition switch to OFF.
2) Disconnect the connector, and measure the 
resistance between main fuse box terminals.

Connector & terminal

(F37) No. 16 — (F143) No. 12:
(F37) No. 18 — (F143) No. 14:

Is the resistance less than 10 
Ω?

Repair or replace 
the harness 
between A/C lock 
sensor and main 
fuse box.

Replace the main 
fuse box.