Subaru Legacy IV (2008 year). Manual - part 988

AC(diag)-4

General Description

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

5. CONTROL SWITCHES

Start the engine and warm up completely.
1) Inspection using switches

2) Inspection of compressor operation

3) Inspection of illumination control

No.

Point to check

Switch operation

Judgement standard

1

OFF switch

Press the OFF switch.

Setting temperature display goes out.
• Blower fan: OFF
• Inlet opening: FRESH
• Compressor: OFF

2

AUTO switch, driver’s 
side temperature con-
trol dial and passen-
ger’s side temperature 
control dial

1) Press the AUTO switch.
2) Turn the temperature control dial to the left 
fully, and set to 18°C (65°F) (maximum cool posi-
tion).

AUTO display illuminates.
• Outlet air temperature: COOL
• Blower fan: HI (AUTO)
• Outlet opening: FACE
• Inlet opening: AUTO
• Compressor: AUTO

3) Turn the temperature control dial to the right 
slowly, and change the setting from 18°C (65°F) 
(maximum cool position) to 32°C (85°F).

• Outlet air temperature: COOL 

o HOT

• Blower fan: AUTO
• Outlet opening: FACE 

o B/L o FOOT

• Inlet opening: AUTO
• Compressor: AUTO

4) Turn the temperature control dial to the right 
fully, and set to 32°C (85°F) (maximum hot posi-
tion).

• Outlet air temperature: HOT
• Blower fan: HI (AUTO)
• Outlet opening: FOOT
• Inlet opening: FRESH (AUTO)
• Compressor: AUTO

3

Defroster switch

Press the defroster switch.

Defroster switch indicator illuminates.
• Outlet air temperature: AUTO
• Blower fan: AUTO
• Outlet opening: DEF
• Inlet opening: FRESH
• Compressor: ON

4

FRESH/RECIRC
switch

Press the FRESH/RECIRC switch.

Inlet opening switches RECIRC 

o FRESH or 

FRESH

o RECIRC each time pressing the 

switch.

5

MODE switch

Press the MODE switch.

Outlet opening switches FACE 

o B/L o

FOOT 

o F/D each time pressing the switch.

6

FAN switch

Press the FAN switch (+).

Inlet opening switches LO 

o M1 o M2 o M3 

o M4 o HI each time pressing the switch.

No.

Point to check

Switch operation

Judgement standard

1

Compressor

1) Turn the A/C switch to ON.
2) Set the FAN switch between LO and HI.

Compressor: ON

No.

Point to check

Switch operation

Judgement standard

1

Illumination

Turn the lighting switch to ON.

Illumination comes on.

AC(diag)-5

Electrical Component Location

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

3. Electrical Component Location

A: LOCATION

1. ENGINE COMPARTMENT

(1)

A/C compressor

(3)

Pressure switch

(4)

Ambient sensor

(2)

A/C 

relay

  

  

AC-00896

(2)

(4)

(1)

(3)

AC-00813

(1)

(2)

AC-01603

AC-00814

(3)

AC-00816

(4)

AC(diag)-6

Electrical Component Location

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

2. PASSENGER COMPARTMENT

(1)

Evaporator sensor

(4)

Blower motor

(7)

Mode door actuator

(2)

Passenger’s side air mix door 
actuator

(5)

Sunload sensor

(8)

In-vehicle sensor

(6)

Intake door actuator

(9)

Driver’s side air mix door actuator

(3)

Auto A/C control module

(7)

(6)

(4)

(3)

(2)

(1)

(5)

(9)

(8)

AC-01595

 AC-00898

(1)

(2)

(7)

(3)

(4)

(6)

AC-00900

AC-00899

(5)

AC-01164

(9)

AC(diag)-7

Auto A/C Control Module I/O Signal

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

4. Auto A/C Control Module I/O Signal

A: ELECTRICAL SPECIFICATION

Terminal No.

Remarks

Measuring condition

Standard

1

Battery power supply

Ignition switch: OFF

Battery voltage

3

Mode door actuator position signal

Mode door: FACE position

4 V

Mode door: DEF position

1 V

4

Air mix door actuator (passenger’s 
side) position signal

Air mix door: Maximum cool position

4 V

Air mix door: Maximum hot position

1 V

5

In-vehicle sensor

Ignition switch: ON

25°C: 1 — 5 V
40°C: 1 — 5 V

6

Sunload sensor

Ignition switch: ON, With Sunload (No sunload: 0 V)

Sunlight: 3 V

Room light: 3 V

8

Each potentiometer and sunload 
sensor power supply

Ignition switch: ON

5 V

9

CAN  LO

 

— 

*1

10

CAN HI

 — 

*1

11

Blower motor voltage feedback

Ignition switch : ON, Blower switch : ON

0.45 — 10 V

12

Blower motor control signal

Ignition switch : ON, Blower switch : ON

9.05 V

13

RAM monitor Tx

Outputs RAM value when No. 33 (RAMver) terminal is 
grounded

*1

14

RAM monitor Rx

*1

15

Magnet clutch ON request signal 
output sensor ground

Ignition switch: ON, Blower switch: ON, A/C switch: ON

HI: 5.5 V

LO: 2.0 V

16

Mode servo drive signal

When actuator is operating
16(+) — 36(–): Turns towards FACE side
16 (–) — 36 (+): rotate to the DEF side
16-36 short: brake

0 or 12 V

36

17

Air mix door actuator (passenger’s 
side) drive signal

When actuator is operating
17(+) — 37(–): Turns towards COOL side
17 (–) — 37 (+): rotate to the HOT side
17-37 short: brake

0 or 12 V

37

18

Air mix door actuator (driver’s seat)

When actuator is operating
18(+) — 38(–): Turns towards COOL side
18 (–) — 38 (+): rotate to the HOT side
18-38 short: brake

0 or 12 V

38

B282

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AC-01515