Subaru Legacy 2002 Service Manual page 2777

RELAY AND FUSE
HVAC System (Heater, Ventilator and A/C)
B: INSPECTION
S701287A10
S4M0577A
(3) — (4): Continuity exists.
(1) — (2): No continuity
While applying battery voltage to the cable
between (3) and (4), check continuity between (1)
and (2).
If no continuity exists, replace the relay with a new
one.
AC-44