Subaru Legacy 2005 Service Manual page 3514

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)
Step
7 CHECK A/C ON SIGNAL.
1) Turn the ignition switch to OFF.
2) Connect the A/C relay and all disconnected
connectors.
3) Start the engine and turn the A/C switch to
ON.
4) Turn the temperature control dial at maxi-
mum cool position.
5) Measure the voltage between auto A/C
control module harness connector terminal
and chassis ground.
Connector & terminal
(B283) No. 6 (+) — Chassis ground (
8 CHECK HARNESS BETWEEN AUTO A/C
CONTROL MODULE AND ECM.
1) Turn the ignition switch to OFF.
2) Disconnect the harness connector of auto
A/C control module and ECM.
3) Measure the resistance in harness
between auto A/C control module connector
and ECM connector.
Connector & terminal
2.0 L turbo model, 3.0 L model and 2.5 L
EC, K4, EK model
(B283) No. 6 — (B137) No. 17:
2.0 L non-turbo model and 2.5 L KS, KA
model
(B283) No. 6 — (B135) No. 20:
9 CHECK MAGNET CLUTCH ON SIGNAL.
1) Stop the engine and turn the A/C switch to
OFF.
2) Turn the ignition switch to ON.
3) Measure the voltage between ECM con-
nector terminal and chassis ground.
Connector & terminal
2.0 L turbo model, 3.0 L model and 2.5 L
EC, K4, EK model
(B135) No. 33 (+) — Chassis ground (
2.0 L non-turbo model and 2.5 L KS, KA
model
(B135) No. 35 (+) — Chassis ground (
10 CHECK MAGNET CLUTCH ON SIGNAL.
1) Start the engine and turn the A/C switch to
ON.
2) Turn the temperature control dial at maxi-
mum cool position.
3) Measure the voltage between ECM con-
nector terminal and chassis ground.
Connector & terminal
2.0 L turbo model, 3.0 L model and 2.5 L
EC, K4, EK model
(B135) No. 33 (+) — Chassis ground (
2.0 L non-turbo model and 2.5 L KS, KA
model
(B135) No. 35 (+) — Chassis ground (
Diagnostics for A/C System Malfunction
Is the voltage more than 5.5 V? Go to step 9.
−
):
Is the resistance less than 1
Ω?
Is the voltage more than 10 V? Go to step 10.
−
):
−
):
Is the voltage 0 V?
−
):
−
):
AC(diag)-22
Check
Replace the auto
A/C control mod-
ule.
Go to step 11.
Yes No
Go to step 8.
Repair the har-
ness.
Check the harness
for open or short
circuit between A/
C relay and ECM.
Replace the ECM.