Subaru 2004 Forester, Service Manual

Page: 67 / 622

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.