Subaru Forester 2004 - General Diagnostic Table

AC-41
HVAC SYSTEM (AUTO A/C)(DIAGNOSTIC)
General Diagnostic Table
9. General Diagnostic Table
A: INSPECTION
Symptom Problem parts
A/C system fails to operate.
•Fuse
• Connector (Poor contact)
•Ground
• Auto A/C control module
• Blower fan motor
• Blower fan relay
• A/C Relay
• Compressor (Magnet clutch)
• Evaporator sensor
Fuse is blown out.
•Fuse
• Connector (Poor contact)
Illumination cannot dim.
•Fuse
• Connector (Poor contact)
• Auto A/C control module
Blower fan does not rotate or fan speed cannot be controlled.
•Fuse
• Connector (Poor contact)
•Ground
• Auto A/C control module
• Blower fan motor
• Blower fan relay
Unable to switch suction vents.
• Connector (Poor contact)
• Auto A/C control module
• Intake door actuator
Unable to switch blow vents.
• Connector (Poor contact)
• Auto A/C control module
• Mode door actuator
Compartment temperature does not increase. (No hot air is dis-
charged.)
• Connector (Poor contact)
• Auto A/C control module
• Air mix door actuator
• In-vehicle sensor, ambient sensor, evaporator sensor and
sunload sensor
• In-vehicle sensor aspirator hose
Compartment temperature does not decrease. (No cool air is
discharged.)
• Connector (Poor contact)
• Auto A/C control module
• Air mix door actuator
• A/C Relay
• Compressor (Magnet clutch)
• Radiator fan motor
• Radiator fan relay
• In-vehicle sensor, ambient sensor, evaporator sensor and
sunload sensor
• In-vehicle sensor aspirator hose
Compartment temperature is higher or lower than setting tem-
perature.
• Auto A/C control module
• Air mix door actuator
• In-vehicle sensor, ambient sensor, evaporator sensor and
sunload sensor
• In-vehicle sensor aspirator hose
Compartment temperature does not quickly respond to setting
temperature.
• Air mix door actuator
• In-vehicle sensor, ambient sensor, evaporator sensor and
sunload sensor
• In-vehicle sensor aspirator hose
Radiator fan does not rotate during A/C operation.
• Radiator fan motor
• Radiator fan relay