Subaru Legacy 2003 Service Manual page 3478

2. General Description
A: CAUTION
1) Never connect the battery in reverse polarity.
• The auto A/C control module may be destroyed
instantly.
2) Do not disconnect the battery terminals while the
engine is running.
• A large counter electromotive force will be gener-
ated in the alternator, and this voltage may damage
electronic parts such as A/C control module.
3) Before disconnecting the connectors of each
sensor and the A/C control module, be sure to turn
off the ignition switch.
• Otherwise, the Auto A/C control module may be
damaged.
4) Every auto 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 (A/C control module) and junction
box.
CAUTION:
• All airbag system wiring harness and con-
nectors are colored yellow. Do not use electri-
cal test equipment on these circuits.
• Be careful not to damage Airbag system wir-
ing harness when servicing the A/C control
panel (A/C control module) and junction box.
B: INSPECTION
Before performing diagnosis, check the following
items which might affect engine problems.
1. BATTERY
1) Measure battery voltage and specific gravity of
electrolyte.
Standard voltage: 12 V
Specific gravity: Above 1.260
2) Check the condition of the fuses for A/C, heater
and other fuses.
(a) Main fuse box
3) Check the condition of the harnesses and har-
ness connectors connection.
GENERAL DESCRIPTION
( a )
AC-00309
AC-5
HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)
2. ASPIRATOR HOSE
1) Turn ignition switch to ON.
2) Push "DEF" switch and then blower fan switch to
turn the blower fan to maximum speed.
OUT.TEMP
AUTO
OFF
3) Firmly hold a thin thread (b) in front of the in-ve-
hicle sensor suction port (a) for the auto A/C control
unit and check that the thread moves towards the
port indicating that air is being sucked into the port.
NOTE:
• Ensure the thread does not get sucked into the
port.
4) If the thread does not move at all, remove the
auto A/C control unit <Ref. to AC-34, REMOVAL,
Control Unit.> and check for improper connection
of the aspirator hose (a) and auto A/C control unit
and secure as necessary.
A/C
AC-00310
( b )
( a )
AC-00311
( a )
AC-00312