Subaru Impreza 2003 Service Manual page 3309

4. HOW TO DETERMINE A SHORT CIR-
CUIT
1) Test lamp method:
Connect a test lamp (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 power supply. If the test lamp goes
out when a connector is disconnected, the wiring
between that connection and next connector (far-
ther from the power supply) is shorted.
Test lamp
Fuse holder
2) Ohmmeter method:
Disconnect all affected connectors, and check the
continuity between each connector and ground.
When the ohmmeter indicates continuity between a
particular connector and ground, that the connector
is shorted.
Continuity does not exist.
BASIC DIAGNOSTICS PROCEDURE
Shorted wiring
WI-00099
Shorted connector
Continuity exists.
WI-00100
WI-5
WIRING SYSTEM