Subaru Legacy 2005 Service Manual page 4220

WIRING SYSTEM
3. HOW TO DETERMINE AN OPEN CIR-
CUIT
1) WITH VOLTMETER:
An open circuit is determined by measuring the
voltage between respective connectors and ground
using a voltmeter, starting with the connector clos-
est to the power supply. The power supply must be
turned ON so that current flows in the circuit. If volt-
age is not present between a particular connector
and ground, the circuit between that connector and
the previous connector is open.
V
No voltage is present
Voltage is present
2) WITH OHMMETER:
Disconnect all connectors affected, and check con-
tinuity in the wiring between adjacent connectors.
When the ohmmeter indicates "infinite", the wiring
is open.
Continuity exists.
4. HOW TO DETERMINE A SHORT CIR-
CUIT
1) WITH TEST LIGHT:
Connect a test light (rated at approx. 3 watts) in
place of the blown fuse and allow current to flow
through the circuit. Disconnect one connector at a
time from the circuit. Starting with the one located
farthest from the power supply. If the test light goes
out when a connector is disconnected, the wiring
Basic Diagnostic Procedure
Open circuit or wiring
V
WI-02742
Open circuit
Continuity does not exist.
WI-02743
between that connector and the next connector
(farther from the power supply) is shorted.
2) WITH OHMMETER:
Disconnect all affected connectors, and check con-
tinuity between each connector and ground. When
the ohmmeter indicates continuity between a par-
ticular connector and a ground, that connector is
shorted.
Continuity does not exist.
C: HOW TO READ WIRING DIA-
GRAMS
1. WIRING DIAGRAM
The wiring diagram of each system is illustrated so
that you can understand the path through which the
electric current flows from the battery.
Sketches and codes are used in the diagrams.
They should read as follows:
• Each connector and its terminal position are indi-
cated by a sketch of the connector in a disconnect-
ed state which is viewed from the front.
4
Viewed from this direction
WI-4
Test lamp
Shorted wiring
Fuse holder
WI-02744
Shorted connector
Continuity exists.
WI-02745
1
3
WI-02746
2
4