Subaru Legacy (2005 year). Manual - part 873

AC(diag)-9

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

Auto A/C Control Module I/O Signal

*1: Unable to measure the voltage for digital signal.

B: WIRING DIAGRAM

1. AIR CONDITIONER AUTO A/C MODEL

<Ref. to WI-189, WIRING DIAGRAM, Air Conditioning System.>

B15, B16

Control panel

—

*1

Terminal No.

Remarks

Measuring conditions

Specification

AC(diag)-10

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

Diagnostic Chart for Self-Diagnosis

5. Diagnostic Chart for Self-Diagnosis 

A: OPERATION

NOTE:
For A/C system self-diagnosis, there is one that checks the control panel, and the other that checks the whole
control system (sensor, actuator, blower motor, etc.). Perform the self-diagnosis for control panel first, and
then perform the self-diagnosis for control system.

(A)

LHD model

(B)

RHD model

(1)

Defroster switch

(4)

A/C switch

(7)

OFF switch

(2)

Rear window defogger switch

(5)

Fan switch

(8)

Temperature control dial (AUTO 
switch)

(3)

Air flow control switch

(6)

FRESH/RECIRC switch

AC-01253

(8)

(7)

(6)

(5)

(4)

(3)

(2)

A/C

A/C

OFF

MODE

AUTO

PUSH AUTO/TEMP

(1)

(3)

(4)

(5)

(6)

(7)

A/C

(2)

(1)

(8)

PUSH AUTO/TEMP

A/C

MODE

OFF

AUTO

(A)

(B)

AC(diag)-11

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

Diagnostic Chart for Self-Diagnosis

1. A/C CONTROL PANEL SELF-DIAGNOSIS

Step

Check

Yes

No

1

SET SELF-DIAGNOSIS MODE BY OPERAT-
ING A/C CONTROL PANEL.
1) Turn the ignition switch to OFF.
2) Turn the ignition switch to ON with the 
defroster switch and A/C switch pressed.
3) The screen display and indicator illuminate.

Does the self-diagnosis mode 
operate?

Go to step 2.

<Ref. to AC(diag)-
15, A/C OR SELF-
DIAGNOSIS SYS-
TEMS DO NOT 
OPERATE, Diag-
nostics for A/C 
System Malfunc-
tion.>

2

CHECK DISPLAY AND INDICATOR.
Check the display and all indicators illuminate.

Do the display and all indica-
tors illuminate?

Go to step 3.

Replace the A/C 
control panel.

3

CHECK SWITCH AND TEMPERATURE CON-
TROL DIAL INPUT.
According to the switch check table, press 
each switch or turn the temperature control 
dial, and check the relative screen display and 
indicators illuminate. <Ref. to AC(diag)-12, 
SWITCH CHECK TABLE, OPERATION, Diag-
nostic Chart for Self-Diagnosis.>

Does the screen display 
related to each switch and dial 
input illuminate?

Go to step 4.

Replace the A/C 
control panel.

4

CHECK A/C CONTROL PANEL COMMUNI-
CATION.
1) Turn the ignition switch to OFF.
2) Disconnect the auto A/C control module 
harness connector.
3) Using a suitable lead wire, short the termi-
nal No. 15 and No. 16 of auto A/C control mod-
ule harness connector (B283).
4) Turn the ignition switch to ON with the rear 
defogger switch and A/C switch pressed.
5) When no malfunction occurs in the control 
panel communication, “CL” is displayed in the 
screen; and when malfunction occurs, “OP” is 
displayed.

Is “CL”  displayed in the 
screen?

A/C control panel 
is normal. Turn the 
ignition switch to 
OFF, and connect 
the auto A/C con-
trol module har-
ness connector.

Replace the A/C 
control panel.

AC(diag)-12

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

Diagnostic Chart for Self-Diagnosis

2. SWITCH CHECK TABLE

(A)

LHD model

(B)

RHD model

Switch

Display screen

Switch

Display screen

A/C switch

(9)

FAN switch (+)

(6)

AUTO switch

(7)

FAN switch (

−)

(5)

Air flow control switch

(10)

Temperature control dial (Right 

turn)

(3)

FRESH/RECIRC

(8)

Temperature control dial (Left 

turn)

(11)

Defroster switch

(1) (2)

OFF switch

(4)

Rear defogger switch

(12)

AC-00902

A/C

OFF

MODE

PUSH AUTO/TEMP

PUSH AUTO/TEMP

A/C

MODE

OFF

(A)

(B)

(8)

(10)

(11)

(9)

(2)

(3) (4)

(5)

(6)

(7)

A/C

AUTO

(4)

(5)

(6)

(8)

(7)

AUTO

(9)

A/C

(10)

(11)

(2)

(3)

(1)

(12)

(1)

(12)