Mitsubishi Galant (2004+). Manual - part 1705

HEATER CONTROL

HEATER, AIR CONDITIONING AND VENTILATION

55-9

The features of the heater controller described below 
are designed for better operation and easier visual 
recognition.

•

Enlargement of the dials

•

Improvement of operational response from incor-
poration of electronics in temperature control dial 
and mode selection dial <vehicles with manual 
A/C>

•

Larger display labels 

•

A/C system display added to the multi-center dis-
play <vehicles with multi-center display (middle 
grade type) >

•

Coordinated illumination with the same ice-blue 
LED illumination for the combination meter and 
audio controls <vehicles with auto A/C or manual 
A/C MID (middle grade type) >

•

Coordinated illumination with the same white illu-
mination for 1DIN audio (low grade type)

•

Easier visual recognition with green used for the 
A/C indicator

•

Better performance when cooling is set at the 
highest level from the addition of a maximum A/C 
position on the temperature control dial <vehicles 
with manual A/C>

•

Accidental fogging of windows due to user error 
is prevented by linking with defroster and fixing of 
internal/external air switching damper in an open 
position

•

Optimal blowing mode and fan power control 
based on data from external temperature sensor, 
sunlight sensor, and interior temperature sensor 
<vehicles with automatic A/C>

•

Blowing mode can now be controlled automati-
cally, separately from the fan level set by the 
user, by setting the mode selection dial to auto-
matic <vehicles with automatic A/C>

•

Fan power can now be controlled automatically, 
separately from the mode selection set by the 
user, by setting the fan dial to automatic <vehi-
cles with automatic A/C>

.

DEFOGGER TIMER
Automatic shutoff by the heater controller (by the A/C-ECU) 
after approximately 17 minutes, to prevent battery drain if the 
defogger is switched on and the user forgets to switch it off.

.

A/C PRESSURE SENSOR
This sensor constantly monitors the refrigerant pressure for 
changes, emitting signals as voltage. The voltage emitted from 
the sensor is received by the heater controller (A/C-ECU), 
which issues power train control module communication for 
engine control based on the air conditioner load.

.

AC306670

<AIR CONDITIONER INFORMATION DISPLAY>

AB

<MULTI-CENTER DISPLAY>

AC005454AB

Refrigerant pressure (MPa)

Output voltage 
(V)

0

1

2

3

5

4

1

2

3

A/C COMPRESSOR

HEATER, AIR CONDITIONING AND VENTILATION

55-10

DETECTION CONTROL FOR REFRIGERANT LEAKS
If the external temperature sensor and A/C pressure sensor 
signal the heater controller (A/C-ECU) that the refrigerant pres-
sure has dropped below a prescribed level or has reached an 
abnormal level, the air conditioning system is stopped and the 
A/C indicator blinks to notify users of malfunction.

.

CAN COMMUNICATION
The air conditioner receives the following kinds of 
signals through CAN signals:

The air conditioner transmits the following kinds of 
signals through CAN signals:

A/C COMPRESSOR

M2551001100042

A scrolling compressor with greater compression efficiency is 
used to improve the cooling performance when idling. Com-
pressor discharge cavity capacity has been expanded to 
reduce discharge pulse, vibration, and noise.

Signal Identification

Transmitter ECU

Engine coolant temperature signal

Powertrain control module

Vehicle speed signal
Engine speed signal
A/C information signal
Vehicle stop signal

Signal Identification

Receiver ECU

A/C pressure signal

Powertrain control module

A/C switch signal
Set temperature signal

Multi-center display (middle grade type)

Ambient temperature signal
Air outlet mode signal
Fan air volume signal

AC306239

DISCHARGE CAVITY CAPACITY

AB

CONDENSER

HEATER, AIR CONDITIONING AND VENTILATION

55-11

A/C COMPRESSOR CLUTCH WITH THERMAL 
FUSE

A thermal fuse is installed in the A/C compressor field core. If 
the compressor fails, the thermal fuse will be blown due to fric-
tion heat produced by the drive belt and locked compressor. 
This deenergizes the A/C compressor clutch and allows the 
compressor to run freely.

CONDENSER

M2551001400032

•

Improved cooling performance from a larger condenser

•

Combination of condenser with receiver in a single unit and 
minimization of pipe junctions to reduce refrigerant leaks

•

Incorporation of the radiator into the condenser for reduced 
vibration to the body and improved effectiveness of the 
chassis dynamic damper.

DUCT

M2551001300046

The fan level and defroster performance have been 
improved by using the following: 

•

Greater blowing power from incorporation of a 
new model of heater unit

•

Improved defroster performance from a cur-
rent-type defroster

•

If the outside temperature is cold and the fan 
level is too low, the blowing mode is switched to 
automatic for a higher level of defrosting power

•

Larger area for vents on the instrument panel air 
outlets

AC209049AC

RECEIVER

CONDENSER

AC306257

TO FRONT DOOR WINDOW
(SIDE DEFROSTER)

SIDE VENTILATOR

TO PASSENGER SEAT FOOTWELL

SIDE VENTILATOR

TO WINDSHIELD (DEFROSTER)

TO FRONT DOOR WINDOW
(SIDE DEFROSTER)

AB

CENTER 
VENTILATOR

TO REAR SEAT FOOTWELL 
(VEHICLE WITH REAR DUCT)

TO DRIVER SEAT FOOTWELL

TO REAR SEAT FOOTWELL 
(VEHICLE WITH REAR DUCT)

VENTILATION SYSTEM

HEATER, AIR CONDITIONING AND VENTILATION

55-12

VENTILATION SYSTEM

M2551002000208

Fresh air is sucked from the front deck and 
exhausted through the air outlet behind the rear 
bumper. Optimizing areas of the outside air induction 
hole and the air outlet improves ventilated air 
amount, reducing noise. 

AC303135

AC302229

AC306247

REAR VENTILATOR DUCT

AB