2004 SUBARU FORESTER sensor

AC-33
HVAC SYSTEM (AUTO A/C)(DIAGNOSTIC)
Diagnostic Procedure for Sensors
 RHD model
AC-00884
A:
i48B:
i49B:
i10
12345678
910 11 12 13 14 15 1612345678910
11 12 13 14 15 16 17 18 19 20
3
4 128910 11
12 13 14 15 16 17 18 19 20 21 22 23 24567
i41
B202
B202
B:
i10
COMBINATION
METER
A:
i48B:
i49
3 A14
B30
123456789101112131415161718192021222324252627282930
AUTO A/C
CONTROL
MODULE
i2
B37
141521
B24
B25
1817
B100F2F78AMBIENT
SENSOR
F2
12
F78
21
1413 16
: MT MODEL
: AT MODEL
3
4 128910
11
12 13 14 15 16 17 18 19 20 21 225673
4 12 8
910 11
12 13 14 15 16 17 185
67
i2 :
i2 :
MT AT
AT
MT AT MT

AC-34
HVAC SYSTEM (AUTO A/C)(DIAGNOSTIC)
Diagnostic Procedure for Sensors
Step Check Yes No
1 CHECK HARNESS CONNECTOR BETWEEN
AUTO A/C CONTROL MODULE AND COM-
BINATION METER.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from auto A/C
control module and combination meter.
3) Measure the resistance in harness
between auto A/C control module and combi-
nation meter.
Connector & terminal
(i10) No. 30 — (i48) No. 14:Is the resistance less than 1
Ω?Go to step 2.Repair the har-
ness between auto
A/C control mod-
ule and combina-
tion meter.
2 CHECK AMBIENT SENSOR CIRCUIT.
Check the ambient sensor circuit. 8, CHECK OUTSIDE TEMPERATURE INDI-
CATOR, INSPECTION, Combination Meter
System.>Is the ambient sensor circuit
normal?Go to step 3.Repair the ambi-
ent sensor circuit.
3 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 A/C
control module.

AC-35
HVAC SYSTEM (AUTO A/C)(DIAGNOSTIC)
Diagnostic Procedure for Sensors
B: IN-VEHICLE SENSOR
TROUBLE SYMPTOM:
 Blower fan speed, outlet port and inlet port do not change after turning the AUTO switch to ON.
 Malfunction related to ambient sensor is indicated in self diagnosis.
WIRING DIAGRAM:
AC-00157
A:
i48B:
i49
12345678
910 11 12 13 14 15 1612345678910
11 12 13 14 15 16 17 18 19 20
i55 :
IN-VEHICLE
SENSOR
A:
i48B:
i49
A16
1
B12
2
12
AUTO A/C
CONTROL
MODULE
LHD
LHD
RHD
RHD
LHD
RHD
LHD
RHD
924
B314 :
: LHD MODEL
: RHD MODEL
LHD
RHD
LHD
RHD
LHD
RHD
i55 :
B314 :
LHD
RHD
3
4 128910 11
12 13 14 15 16 17 18 19 20 21 22 23 24567
B202
B202
i41

AC-36
HVAC SYSTEM (AUTO A/C)(DIAGNOSTIC)
Diagnostic Procedure for Sensors
Step Check Yes No
1 CHECK IN-VEHICLE SENSOR.
1) Turn the ignition switch to OFF.
2) Remove the instrument panel lower cover.
3) Disconnect the connector from in-vehicle
sensor.
4) Measure the resistance between connector
terminals of in-vehicle sensor.
Te r m i n a l s
No. 1 — No. 2:Is the resistance approx. 2.7
kΩ at 20°C (68°F)?Go to step 2.Replace the in-
vehicle sensor.
2 CHECK INPUT SIGNAL FOR IN-VEHICLE
SENSOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between in-vehicle
sensor harness connector terminal and chas-
sis ground.
Connector & terminal
LHD model:
(i55) No. 2 (+) — Chassis ground (
−):
RHD model:
(B314) No. 2 (+) — Chassis ground (
−):Is the voltage approx. 5 V? Go to step 6.Go to step 3.
3 CHECK AUTO A/C CONTROL MODULE
OUTPUT SIGNAL.
1) Turn the ignition switch to OFF.
2) Remove the auto A/C control module.
3) Turn the ignition switch to ON.
4) Measure the voltage between connector
terminals of auto A/C control module.
Connector & terminal
(i49) No. 12 (+) — (i48) No. 16:Is the voltage approx. 5 V? Go to step 4.Go to step 6.
4 CHECK HARNESS BETWEEN AUTO A/C
CONTROL MODULE AND IN-VEHICLE SEN-
SOR.
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 in-vehi-
cle sensor.
Connector & terminal
LHD model:
(i55) No. 2 — (i49) No. 12:
RHD model:
(B314) No. 2 — (i49) No. 12:Is the resistance less than 1
Ω?Go to step 5.Repair the har-
ness between auto
A/C control mod-
ule and in-vehicle
sensor.
5 CHECK HARNESS BETWEEN AUTO A/C
CONTROL MODULE AND IN-VEHICLE SEN-
SOR.
Measure the resistance in harness between
auto A/C control module and in-vehicle sensor.
Connector & terminal
LHD model:
(i55) No. 1 — (i48) No. 16:
RHD model:
(B314) No. 1 — (i48) No. 16:Is the resistance less than 1
Ω?Go to step 6.Repair the har-
ness between auto
A/C control mod-
ule and in-vehicle
sensor.
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-37
HVAC SYSTEM (AUTO A/C)(DIAGNOSTIC)
Diagnostic Procedure for Sensors
C: EVAPORATOR SENSOR
WIRING DIAGRAM:
AC-00158
A:
i48B:
i49B256
12345678
910 11 12 13 14 15 1612345678910
11 12 13 14 15 16 17 18 19 203
4 128910 11
12 13 14 15 16 17 18 19 20 21 22 23 24567
B202
B202
i41
B256
A:
i48B:
i49
A16
5
1
B23
15
123
EVAPORATOR
SENSOR
AUTO A/C
CONTROL
MODULE
119RHD LHD
: LHD MODEL
: RHD MODELLHD
RHD

AC-38
HVAC SYSTEM (AUTO A/C)(DIAGNOSTIC)
Diagnostic Procedure for Sensors
Step Check Yes No
1 CHECK EVAPORATOR SENSOR.
1) Turn the ignition switch to OFF.
2) Remove the glove box.
3) Disconnect the connector from evaporator
sensor.
4) Measure the resistance between connector
terminals of evaporator sensor.
Te r m i n a l s
No. 1 — No. 2:Is the resistance approx. 2.7
kΩ at 20°C (68°F)?Go to step 2.Replace the evap-
orator sensor.
2 CHECK INPUT SIGNAL FOR EVAPORATOR
SENSOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between connector
(B256) terminal and chassis ground.
Connector & terminal
(B256) No. 1 (+) — Chassis ground (
−):Is the voltage approx. 5 V? Go to step 5.Go to step 3.
3 CHECK AUTO A/C CONTROL MODULE
OUTPUT SIGNAL.
1) Turn the ignition switch to OFF.
2) Remove the auto A/C control module.
3) Turn the ignition switch to ON.
4) Measure the voltage between connector
terminals of auto A/C control module.
Connector & terminal
(i49) No. 2 (+) — (i48) No. 16 (
−):Is the voltage approx. 5 V? Go to step 4.Go to step 6.
4 CHECK HARNESS CONNECTOR BETWEEN
AUTO A/C CONTROL MODULE AND EVAP-
ORATOR 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 evapo-
rator sensor.
Connector & terminal
(B256) No. 1 — (i49) No. 2:Is the resistance less than 1Ω? Go to step 5.Repair the open
circuit in harness
between auto A/C
control module
and evaporator
sensor.
5 CHECK HARNESS CONNECTOR BETWEEN
AUTO A/C CONTROL MODULE AND EVAP-
ORATOR SENSOR.
Measure the resistance in harness between
auto A/C control module and evaporator sen-
sor.
Connector & terminal
(B256) No. 3 — (i48) No. 16:Is the resistance less than 1
Ω?Go to step 6.Repair the open
circuit in harness
between auto A/C
control module
and evaporator
sensor.
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-39
HVAC SYSTEM (AUTO A/C)(DIAGNOSTIC)
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-00885
A:
i48B:
i49
12345678
910 11 12 13 14 15 1612345678910
11 12 13 14 15 16 17 18 19 20
3
4 128910 11
12 13 14 15 16 17 18 19 20 21 22 23 24567
B202
B202
i41
i51
A:
i48B:
i49
A16
9
2
B31
12
2223
i3
B38
i51
12
SUNLOAD
SENSOR
AUTO A/C
CONTROL
MODULE
B38
219
32
1234 5610 11 12 13 14 15716
23 3019 20
22 26 27 28 29817
24 3118
25
RHD
1520LHD
LHD
LHD
RHD
RHD
LHD
RHD
LHD
RHD
2019
177i2
B37
: LHD MODEL
: RHD MODEL
LHD
RHD
LHD
RHD
3
4 128910
11 12 13 14 15 16 17 18 19 20 21 22567
i2 :
3
4 128
910 11 12 13 14 15 16 17 18567
i2 :ATMT
AT
: MT MODEL
: AT MODEL
ATMT
MT

AC-40
HVAC SYSTEM (AUTO A/C)(DIAGNOSTIC)
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. 2 (+) — Chassis ground (
−):Is the voltage approx. 5 V? Go to step 4.Go to step 2.
2 CHECK AUTO A/C CONTROL MODULE
OUTPUT SIGNAL.
1) Turn the ignition switch to OFF.
2) Remove the auto A/C control module.
3) Turn the ignition switch to ON.
4) Measure the voltage between connector
terminals of auto A/C control module.
Connector & terminal
(i49) No. 3 (+) — (i48) No. 16 (
−):Is the voltage approx. 5 V? Go to step 3.Go to step 6.
3 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 — (i49) No. 3: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 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 — (i48) No. 16:Is the resistance less than 1
Ω?Go to step 5.Repair the har-
ness between auto
A/C control mod-
ule and sunload
sensor.
5 CHECK INPUT VOLTAGE FOR AUTO A/C
CONTROL MODULE.
1) Connect the connector of 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
(i49) No. 3 (+) — (i48) No. 16 (
−):Is the voltage approx. 2.5 V? Go to step 6.Replace the sun-
load sensor.
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.