2004 SUBARU FORESTER fuse box

AC-42
HVAC SYSTEM (HEATER, VENTILATOR AND A/C)
Relay and Fuse
17.Relay and Fuse
A: LOCATIONB: INSPECTION
While applying battery voltage between the termi-
nals (1) and (2), check continuity between the ter-
minals (3) and (5).
If no continuity exists, replace the relay with a new
one.
(1) Main fuse box (M/B)
(2) Main fan relay
(3) Sub fan relay
(4) A/C relay
(5) Fan mode relay
(6) Main fan fuse
(7) Sub fan fuse
AC-00834
(7) (6) (5) (4)(1) (3) (2)
(1) — (2) Continuity exists.
(3) — (4) Continuity exists.
(3) — (5) No continuity.
AC-00093
4
4
5
2
25
3
3
1
1

AC-3
HVAC SYSTEM (AUTO A/C)(DIAGNOSTIC)
General Description
2. General Description
A: CAUTION
1) Never connect the battery in reverse polarity.
Auto A/C control module may be destroyed instant-
ly.
2) Do not disconnect the battery terminals while the
engine is running.
A large counter electromotive force will be generat-
ed in the generator, and this voltage may damage
electronic parts such as auto A/C control module,
etc.
3) Before disconnecting the connectors of each
sensor and the auto A/C control module, be sure to
turn off the ignition switch.
Auto A/C control module may be damaged.
4) Every A/C-related part is a precision part. Do not
drop them.
5) Airbag system wiring harness is routed near the
A/C control panel (auto A/C control module) and
junction box.
CAUTION:
 For airbag system, yellow-colored wiring har-
ness and connectors are all used. Do not use
the electrical test equipment on these circuits.
 Be careful not to damage the airbag system
wiring harness when servicing the A/C control
panel (auto A/C control module) and junction
box.
B: INSPECTION
Before performing the diagnosis, check the follow-
ing items which might affect A/C system problems.
1. BATTERY
1) Measure battery voltage and specific gravity of
electrolyte.
Standard voltage: 12 V
Specific gravity: More than 1.260
2) Check the condition of the fuses for A/C system
power supply and other fuses.
3) Check the condition of harness and harness
connector connections.
2. ASPIRATOR HOSE
1) Turn the ignition switch to ON, and press the A/
C switch.
2) Turn the temperature control dial at maximum
hot position.
3) Press the defroster switch.
4) Turn the fan speed control dial to 4th position.5) Approach a strip of paper (b) in front of the in-ve-
hicle sensor suction port (a) located in the instru-
ment lower cover, and check that air is being
sucked into the port by seeing the paper moving to-
wards port.
NOTE:
Be careful not to let the paper get sucked into port.
6) If the paper does not move at all, remove the in-
strument panel lower cover MOVAL, Instrument Panel Assembly.> and check
for improper connection of the aspirator hose (a),
in-vehicle sensor and heater unit, and repair them if
necessary.
3. A/C LINE
Check the connection for A/C line (A) and lower
side high-pressure pipe.
4. CONTROL LINKAGE
1) Check the state of mode door linkage.
2) Check the state of air mix door linkage.
3) Check the state of intake door linkage.
AC-00094
(a)
(a)
(b)
AC-00065
(a)
AC-00096
(A)

AC-13
HVAC SYSTEM (AUTO A/C)(DIAGNOSTIC)
Diagnostics for A/C System Malfunction
Step Check Yes No
1 CHECK FUSE.
1) Turn the ignition switch to OFF.
2) Remove the fuse No. 2 from main fuse box.
3) Check the condition of fuse.Is the fuse blown-out? Replace the fuse. Go to step 2.
2 CHECK FUSE.
1) Turn the ignition switch to OFF.
2) Remove the fuse No. 17 from fuse & relay
box.
3) Check the condition of fuse.Is the fuse blown-out? Replace the fuse. Go to step 3.
3 CHECK AUTO A/C CONTROL MODULE
POWER CIRCUIT.
1) Pull out the auto A/C control module con-
nector.
2) Measure the voltage between auto A/C
control module connector terminal and chassis
ground after turning the ignition switch to OFF
position.
Connector & terminal
(i49) No. 4 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 4.Check open or
short circuit in har-
ness between auto
A/C control mod-
ule and fuse.
4 CHECK AUTO A/C CONTROL MODULE
POWER CIRCUIT.
Measure the voltage between auto A/C control
module connector terminal and chassis ground
after turning the ignition switch to ON position.
Connector & terminal
(i49) No. 5 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 5.Check open or
short circuit in har-
ness between auto
A/C control mod-
ule and fuse.
5 CHECK AUTO A/C CONTROL MODULE
GROUND CIRCUIT.
Measure the resistance in harness between
auto A/C control module and chassis ground.
Connector & terminal
(i49) No. 11 — Chassis ground:Is the resistance less than 1
Ω?Go to step 6.Repair the har-
ness for ground
line.
6 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-15
HVAC SYSTEM (AUTO A/C)(DIAGNOSTIC)
Diagnostics for A/C System Malfunction
Step Check Yes No
1 CHECK FUSE.
1) Remove the fuse No. 1, 2 and 17 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 fan speed control dial clockwise.
3) Measure the voltage between blower motor
and chassis ground.
Connector & terminal
(B87) No. 1 (+) — Chassis ground (
−):Is the voltage more than 8 V (at
normal temperature)?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. 1 of blower motor relay, and nega-
tive (−) terminal to terminal No. 3.
4) Measure the resistance between terminals
No. 2 and 4.
Te r m i n a l s
No. 2 — No. 4: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. 1 of blower motor connector, and
negative (−) terminal to terminal No. 2 and No.
5.
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-18
HVAC SYSTEM (AUTO A/C)(DIAGNOSTIC)
Diagnostics for A/C System Malfunction
Step Check Yes No
1 CHECK FUSE.
1) Turn the ignition switch to OFF.
2) Remove the main fan fuse and sub fan fuse
in main fuse box.
3) Check the condition of fuse.Is the fuse blown out? Replace the fuse. Go to step 2.
2 CHECK THE POWER SUPPLY TO PRES-
SURE SWITCH.
1) Disconnect the connector from pressure
switch.
2) Turn the ignition switch to ON.
3) Measure the voltage between harness con-
nector and chassis ground.
Connector & terminal
(F79) No. 1 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 3.Repair the har-
ness for pressure
switch power sup-
ply circuit.
3 CHECK THE HARNESS BETWEEN PRES-
SURE SWITCH AND A/C RELAY HARNESS.
1) Turn the ignition switch to OFF.
2) Remove the A/C relay in the main fuse box.
3) Measure the resistance between A/C relay
and pressure switch connector.
Connector & terminal
(F27) No. 17 — (F79) No. 2:Is the resistance less than 1
Ω?Go to step 4.Repair the har-
ness between A/C
relay and pres-
sure switch.
4 CHECK THE PRESSURE SWITCH.
Measure the resistance between pressure
switch terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance less than 1
Ω?Go to step 5.Replace the pres-
sure switch.
5 CHECK THE A/C CUT SIGNAL CIRCUIT.
1) Disconnect the connector from auto A/C
control module.
2) Measure the resistance between auto A/C
control module and pressure switch connector.
Connector & terminal
(i48) No. 10 — (F79) No. 2:Is the resistance less than 1
Ω?Go to step 6.Repair the har-
ness between auto
A/C control mod-
ule and pressure
switch.
6 CHECK THE A/C ON SIGNAL CIRCUIT.
1) Disconnect the connector from ECM.
2) Measure the resistance between ECM and
auto A/C control module connector.
Connector & terminal
Turbo model
(B137) No. 17 — (i49) No. 17:
Non-turbo model
(B136) No. 11 — (i49) No. 17:Is the resistance less than 1
Ω?Go to step 7.Repair the har-
ness between auto
A/C control mod-
ule and ECM.
7 CHECK A/C RELAY.
1) Remove the A/C relay in main fuse box.
2) Check the A/C relay. INSPECTION, Relay and Fuse.>Is the operation of the relay
OK?Go to step 8.Replace the A/C
relay.
8 CHECK POWER SUPPLY TO MAGNET
CLUTCH OF A/C COMPRESSOR.
1) Turn the ignition switch to OFF, and then
connect the A/C relay connector and all
removed connectors.
2) Start the engine, and turn A/C switch to
ON.
3) Set the temperature control dial to maxi-
mum cold position.
4) Measure the voltage between magnet
clutch harness connector and chassis ground.
Connector & terminal
(F24) No. 1 (+) — Chassis ground (
−):Is the voltage more than 10.5 V
(at normal temperature)?Go to step 9.Repair the har-
ness for power
supply line of A/C
compressor.

AB-39
AIRBAG SYSTEM (DIAGNOSTIC)
Airbag Warning Light Failure
B: AIRBAG WARNING LIGHT REMAINS OFF.
DIAGNOSIS:
 Fuse No. 14 (in fuse box) is blown.
 Body harness circuit is open.
 Airbag warning light is faulty.
 Airbag main harness is faulty.
 Airbag control module is faulty.
CAUTION:
 Before diagnosing the airbag system, be sure to turn the ignition switch to OFF, disconnect the
ground cable from battery, and wait more than 20 seconds before starting to work.
 After replacing the airbag module, seat belt pretensioner, roll connector, control module or sensor,
reconnect each part and confirm that the airbag warning light operates properly.
 When inspecting the airbag main harness, disconnect the airbag module connector of the driver
and passenger seats for safety reasons.
1. LHD MODEL
WIRING DIAGRAM:
AB-00739
12
34561
2345678910123456789101112131415161718192021222324252627282930
B31 i11AB3
i10
B:
C: i10
i11
AIRBAG
WARNING
LIGHTCOMBINATION
METERB9
B8
B10
NO.14
i3B38 28
i2B37 19
5
AIRBAG CONTROL MODULEAB3
B31
AB1
3
3
AIRBAG
CIRCUIT
E
BATTERY
1234567891011121314151617
1819202122232425262728
IGNITION
SWITCH
B: C:

AB-40
AIRBAG SYSTEM (DIAGNOSTIC)
Airbag Warning Light Failure
Step Check Yes No
1 CHECK COMBINATION METER.
Turn the ignition switch to ON, and confirm that
warning lights equipped in the combination
meter are turned on.Do the warning lights not for
airbag turn on?Go to step 2.Repair the combi-
nation meter
power supply.
Combination
Meter System.>
2 CHECK FUSE NO. 14 (IN FUSE&RELAY
BOX).
Remove the fuse No. 14 and perform visual
inspection.Is the fuse No. 14 (in fuse &
relay box) blown out? Replace the fuse
No. 14. If fuse No.
14 blows again, go
to step 3. Go to step 3.
3 CHECK AIRBAG WARNING LIGHT CIRCUIT
(IN COMBINATION METER).
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait more than
20 seconds.
2) Disconnect the connector (AB1) from
(B31).
3) Connect the battery ground cable and turn
the ignition switch to ON.Is the airbag warning light
turned on?Go to step 4.Replace the airbag
warning light bulb
or combination
meter printed cir-
cuit. 10, Combination
Meter Assembly.>
4 CHECK AIRBAG MAIN HARNESS.
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait more than
20 seconds.
2) Connect the connector (AB1) to (B31).
3) Disconnect the connector (AB3) from the
airbag control module. Control Module.>
4) Connect the battery ground cable and turn
the ignition switch to ON.Is the airbag warning light
turned on?Replace the airbag
control module.
Airbag Control
Module.>Replace the airbag
main harness with
body harness.

AB-42
AIRBAG SYSTEM (DIAGNOSTIC)
Airbag Warning Light Failure
Step Check Yes No
1 CHECK COMBINATION METER.
Turn the ignition switch to ON, and confirm that
warning lights equipped in the combination
meter are turned on.Do the warning lights not for
airbag turn on?Go to step 2.Repair the combi-
nation meter
power supply.
Combination
Meter System.>
2 CHECK FUSE NO. 14 (IN FUSE&RELAY
BOX).
Remove the fuse No. 14 and perform visual
inspection.Is the fuse No. 14 (in fuse &
relay box) blown out?Replace the fuse
No. 14. If fuse No.
14 blows again, go
to step 3. Go to step 3.
3 CHECK AIRBAG WARNING LIGHT CIRCUIT
(IN COMBINATION METER).
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait more than
20 seconds.
2) Disconnect the connector (AB1) from
(B31).
3) Connect the battery ground cable and turn
the ignition switch to ON.Is the airbag warning light
turned on?Go to step 4.Replace the airbag
warning light bulb
or combination
meter printed cir-
cuit. 10, Combination
Meter Assembly.>
4 CHECK AIRBAG MAIN HARNESS.
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait more than
20 seconds.
2) Connect the connector (AB1) to (B31).
3) Disconnect the connector (AB3) from the
airbag control module. Control Module.>
4) Connect the battery ground cable and turn
the ignition switch to ON.Is the airbag warning light
turned on?Replace the airbag
control module.
Airbag Control
Module.>Replace the airbag
main harness with
body harness.