Subaru 2004 Forester, Service Manual

Page: 57 / 622

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 <Ref. to EI-40, RE-
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)