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Subaru Legacy III (2000-2003 year). Manual - part 869

AC-12

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

A/C CONTROL MODULE I/O SIGNAL

2. RHD MODEL

(1) A/C control module

(2) To (i49): b

(3) To (i48): a

AC-00316

i49

: b

i48

: a

A/C control modules

AC-13

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

A/C CONTROL MODULE I/O SIGNAL

B: SCHEMATIC

<Ref. to WI-62, SCHEMATIC, Air Conditioning System.>

Content

Connector &

Terminal No.

Signal (V)

BATT voltage (Memory back-up)

a1—a9

BATT voltage,
13 — 14 (engine running)

IGN power supply

a2—a9

Battery voltage (ignition switch ON),
13 — 14 (engine running)

ACC power supply
(OFF: ignition in START or diag-
nosis system reset)

a3—a9

BATT voltage, 0 (engine cranking), BATT voltage during engine starts

Sensor standard voltage

a5—a9

5 (ignition switch ON)

A/C control module ground circuit

a9—body

0 (ignition switch ON) — circuit constantly grounded

Sensor ground circuit

a10—body

0 (ignition switch ON) — circuit constantly grounded

Ambient sensor

a11—a10

Approx. 3.3 (disconnect connector, and ignition switch ON)

Evaporator sensor

a12—a10

Thermometer

a13—a9

Sunload sensor

a5—a4

Approx. 4.2 (disconnect connector, and ignition switch ON)

Air mix door actuator

b1—b11

BATT voltage (AUTO mode) positive “+” at terminal “b1” and negative “–” at
“b11” [temperature set at 18

C (65

F)]; negative “–” at terminal “b1” and pos-

itive “+” at “b11” [temperature set at 32

C (90

F)]

Air mix door actuator P.B.R.

a6—a10

Approx. 0.5 [temperature set at 18

C (65

F) in AUTO mode]

Approx. 4.5 [temperature set at 32

C (90

F) in AUTO mode]

Mode door actuator

a8—a16

BATT voltage (ignition switch ON in MANUAL mode); positive “+” at terminal
“a8” and negative “–” at “a8” (VENT); negative “–” at “a16” and positive “+” at
“a16” (DEF)

Mode door actuator P.B.R.

a14—a10

BATT voltage (ignition switch ON in MANUAL mode)
Approx. 4.5 (VENT); approx. 0.5 (DEF)

Intake door FRS actuator voltage

b2—a9

BATT voltage (DEF switch ON)

Intake door CIRC actuator voltage

b12—a9

BATT voltage (CIRC switch ON)

Blower fan relay

b3—a9

BATT voltage (ignition switch ON, blower switch OFF)

Blower fan relay

b5—a9

0 (ignition ON, manual blower HI)
5 (ignition ON, manual blower LO)

Rear defogger relay

b13—a9

0 (ignition switch ON, Rear DEF switch ON)

A/C relay

a7—a9

BATT voltage (ignition and A/C switches ON)
0 (A/C switch OFF)

Illumination control signal

b10—a9

BATT voltage (ignition and lighting switches ON)

AC-14

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

SELF-DIAGNOSIS PROCEDURE (LHD MODEL)

5. Self-Diagnosis Procedure (LHD Model)

A: OPERATION

(1) Temperature control dial

(3) FRESH/RECIRC switch

(5) MODE switch

(2) AUTO switch

(4) DEF switch

AC-00317

OUT.TEMP

BRIGHT

MODE

AUTO

OFF

ECON

A/C

A/C

AUTO

( 5 )

( 3 )

( 2 )

( 4 )

( 1 )

AC-15

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

SELF-DIAGNOSIS PROCEDURE (LHD MODEL)

Step

Value

Yes

SELECT CONTROL PANEL TO SELF-DIAG-
NOSIS MODE.
1) Turn ignition switch to OFF.
2) While pushing “AUTO” and “FRESH/

RECIRC” switches, start the engine.
Can it be moved to the self-diagnosis
mode?

It can be moved to self-diagno-
sis mode.

Go to step 2.

<Ref. to AC-20, A/
C AND/OR SELF-
DIAGNOSIS SYS-
TEMS DO NOT
OPERATE, Diag-
nostics for A/C
System Failure
(LHD Model).>

CHECK INDICATOR.
1) Turn temperature control dial clockwise by

one click.

2) Make sure that all characters illuminate on

the display.
Does each character illuminate?

Each character illuminates.

Go to step 3.

Go to step 7.

CHECK EACH SENSOR AND EACH POTEN-
TIOMETER.
1) Turn temperature control dial clockwise by

one click.

2) If system has the trouble for each sensor

and/or each potentiometer, DTC is indi-
cated on indicator.

3) If system has no trouble, DTC “20” is indi-

cated on indicator.

NOTE:

When the sunload sensor is checked inside the
passenger compartment or in the shade, DTC
“25” may appear on the indicator. Always check
the sunload sensor in a place where it senses
direct sunlight.
Is the DTC “20” indicated on indicator?

DTC “20” indicated.

Go to step 4.

Perform diagnosis
procedure accord-
ing to the dis-
played DTC. <Ref.
to AC-49, DTC
FOR SENSOR
AND POTENTI-
OMETER, LIST
(LHD MODEL),
List of Diagnostic
Trouble Code
(DTC).>

CHECK DOOR MOTOR POSITION SWITCH.
1) Turn temperature control dial clockwise by

one click.

2) If system has the trouble for each door

position switch, DTC is indicated on indica-
tor.

3) If system has no trouble, DTC “30” is indi-

cated on indicator.
Is the DTC “30” indicated on indicator?

DTC “30” indicated.

Go to step 5.

Perform diagnosis
procedure for
mode door actua-
tor. <Ref. to AC-
58, DTC 31, 32,
33, 34 OR 35
(MODE DOOR
ACTUATOR),
Diagnostic Proce-
dure with Diagnos-
tic Trouble Code
(DTC) (LHD
Model).>