Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 608

AC(diag)-37

Diagnostics with Phenomenon

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

9. Diagnostics with Phenomenon

A: INSPECTION

Symptoms

Faulty parts

A/C system fails to operate.

• Fuse (F/B No. 7, 22, 31)
• Connector (Poor contact)
• Ground
• Auto A/C control module
• Blower fan motor
• Blower fan relay
• A/C relay
• Compressor (Magnet clutch)
• Evaporator sensor
• ECM

Fuse is blown out.

• Fuse (F/B No. 7, 22, 31)
• Connector (Poor contact)

Illumination cannot dim.

• Fuse (F/B No. 7, 22, 31)
• Connector (Poor contact)
• Auto A/C control module

Blower fan does not rotate or fan speed cannot
be controlled.

• Fuse (F/B No. 7, 22, 31)
• Connector (Poor contact)
• Ground
• Auto A/C control module
• Blower fan motor
• Blower fan relay
• Power transistor

Unable to switch suction vents.

• Connector (Poor contact)
• Auto A/C control module
• Intake door actuator

Unable to switch vents.

• Connector (Poor contact)
• Auto A/C control module
• Mode door actuator

Compartment temperature does not rise.
(Warm air does not come out.)

• 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 lower.
(Cold air does not come out.)

• 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 temperature.

• 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 opera-
tion.

• Radiator fan motor
• Radiator fan relay
• ECM

AC(diag)-38

Diagnostics with Phenomenon

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)