Mitsubishi Grandis. Manual - part 325

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-185

33

Rear control fan OFF 
switch<Vehicles with rear 
heater, rear cooler or dual 
automatic A/C>

Rear air volume adjusting 
switch: AUTO

AUTO

Rear air volume adjusting 
switch: 1

Lo

Rear air volume adjusting 
switch: 2

Me

Rear air volume adjusting 
switch: 3

Hi

34

Rear defogger switch

Rear window defogger 
switch: ON

ON

Rear window defogger 
switch: OFF

OFF

35

PTC heater switch 
<Vehicles with rear heater, 
rear cooler or dual 
automatic A/C>

Heater switch ON

ON

Heater switch OFF

OFF

36

Rear fan SW lamp (Front) 
<Vehicles with rear heater, 
rear cooler or dual 
automatic A/C>

Rear fan switch: ON

ON

Rear fan switch: OFF

OFF

37

Rear control OFF SW lamp 
(Front) <Vehicles with rear 
heater, rear cooler or dual 
automatic A/C>

Rear fan switch: ON

ON

38

Rear control OFF SW lamp 
<Vehicles with rear heater, 
rear cooler or dual 
automatic A/C>

Rear air volume adjusting 
switch: OFF

ALL OFF

Rear air volume adjusting 
switch: AUTO

AUTO

Rear air volume adjusting 
switch: 1

Lo

Rear air volume adjusting 
switch: 2

Me

Rear air volume adjusting 
switch: 3

Hi

−

ALL ON

39

PTC heater lamp <Vehicles 
with rear heater or dual 
automatic A/C>

Heater switch ON 

ON

Heater switch OFF

OFF

40

Illuminations power supply

Lighting switch: ON

ON

Lighting switch: OFF

OFF

41

PTC heater relay <Vehicles 
with rear heater or dual 
automatic A/C>

PTC heater relay: ON

ON

PTC heater relay: OFF

OFF

Item No.

Check items

Inspection status

The display contents under 
normal conditions

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-186

ACTUATOR TEST TABLE

M1554005200188

50

Front Temperature setting

−

Display the temperature 
control dial position (18.0 - 
32.0

°C)

51

Rear Temperature setting 
<Vehicles with rear heater, 
rear cooler or dual 
automatic A/C>

−

Display the rear temperature 
control lever position (20.0 - 
30.0

°C)

55

Refrigerant leak

Normal refrigerant level

NORMAL

Checking refrigerant level 

Checking

Defective refrigerant level

Fail

56

Low pressure

Normal refrigerant pressure NORMAL
Checking refrigerant 
pressure

Checking

Defective refrigerant 
pressure

Fail

Item No.

Check items

Inspection status

The display contents under 
normal conditions

Item No.

Check items

Drive content

01

Front blower fan: OFF

Stop

02

Front blower fan: Middle

Middle speed

03

Front blower fan: High

High speed

04

Rear blower fan: OFF <Vehicles with rear 
heater, rear cooler or dual automatic A/C>

Stop

05

Rear blower fan: AUTO <Vehicles with rear 
heater, rear cooler or dual automatic A/C>

AUTO

06

Rear blower fan: Lo <Vehicles with rear heater, 
rear cooler or dual automatic A/C>

Low speed

07

Rear blower fan: Middle <Vehicles with rear 
heater, rear cooler or dual automatic A/C>

Middle speed

08

Rear blower fan: High <Vehicles with rear 
heater, rear cooler or dual automatic A/C>

High speed

09

Condenser fan: OFF

Stop

0A

Condenser fan: 50%

Middle speed

0B

Condenser fan: 100%

High speed

10

F.Air mix dumper motor: 0%

Opening angle: Approximately 0% (MAX 
COOL)

11

F.Air mix dumper motor: 50%

Opening angle: Approximately 50%

12

F.Air mix dumper motor: 100%

Open angle: Approximately 100% (MAX 
COOL)

13

R.Air mix dumper motor: 0% <Vehicles with 
rear heater, rear cooler or dual automatic A/C>

Opening angle: Approximately 0% (MAX 
COOL)

14

R.Air mix dumper motor: 50% <Vehicles with 
rear heater, rear cooler or dual automatic A/C>

Opening angle: Approximately 50%

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-187

CHECK AT A/C-ECU TERMINALS

M1552010300668

15

R.Air mix dumper motor: 100% <Vehicles with 
rear heater, rear cooler or dual automatic A/C>

Open angle: Approximately 100% (MAX 
COOL)

20

Air outlet c/o dumper: FACE

Air outlet at FACE position

21

Air outlet c/o dumper: Bi-Level

Air outlet at FACE/FOOT position

22

Air outlet c/o dumper: FOOT

Air outlet at FOOT position

23

Air outlet c/o dumper: DEF/FOOT

Air outlet at DEF/FOOT position

24

Air outlet c/o dumper: DEF

Air outlet at DEF position

30

In/out changeover dumper: Recirc

Moved to recirculation-side

31

In/out changeover dumper: Fresh

Moved to outside air-side

40

Rear defogger switch: OFF

Rear window defogger OFF

41

Rear defogger switch: ON

Rear window defogger ON

42

PTC heater relay: OFF <Vehicles with rear 
heater or dual automatic A/C>

PTC heater OFF

43

PTC heater relay: ON <Vehicles with rear 
heater or dual automatic A/C>

PTC heater ON (air outlet at FACE or 
DEF position, not operate with blower 
OFF)

50

Idle up request: OFF

Idle rpm (not operate with compressor 
ON)

51

Idle up request: low load

Idle up with low load rpm

52

Idle up request: high lode

Idle up with high load rpm

Item No.

Check items

Drive content

5152 5354 5556 57585960 61

62 6364656667686970 7172

1 2 3 4 5 6 7 8 9 10 111213

20

19

18

17

16

15

14

2122 2324 25 26

313233 3435 36 37 38

39 4041 42 43 44 4546

AC303234

<C-08>

<C-11>

<C-09>

AB

Terminal 
No.

Check items

Check conditions

Normal conditions

1

Sensor earth

Always

0 V

2

Front power transistor 
(DRAIN)

Air volume control dial: Maximum 
air volume (Preset temperature 
18

°C)

0 

− 2 V

3

Front power transistor (GATE) Air volume control dial: Maximum 

air volume (Preset temperature 
18

°C)

System voltage

4

Back-up power supply

Always

System voltage

5

ACC power supply

Ignition switch: ACC

System voltage

6

IG2 power supply

Ignition switch: IG2

System voltage

7

Earth

Always

0 V

8~10

−

−

−

11

Compressor relay input

Compressor relay: ON

System voltage

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-188

12

Rear window defogger relay

Rear window defogger relay: ON

0 

− 1 V

13

PTC heater switch indicator 
<Vehicles with rear heater or 
dual automatic A/C>

PTC heater switch: ON

0 

− 1 V

PTC switch: OFF

0 V

14

Sensor power supply:

Ignition switch: IG2

5 V

15

Rear temperature control 
lever <Vehicles with dual 
automatic A/C>

Rear temperature control lever 
MAX HOT position

0 V

16, 17

−

−

−

18

Interior temperature sensor

Sensor probe temperature: 25

°C 

(4k

Ω)

2.1 

− 2.7 V

19

Air thermo sensor

Sensor probe temperature: 25

°C 

(4k

Ω)

2.1 

− 2.7 V

20

Front air mix damper motor 
(Potentiometer input)

Front air mix damper motor MAX 
HOT position

1.2 

− 1.6 V

21

Air outlet changeover damper 
motor (Potentiometer input)

DEF position

0.5 

− 0.8 V

22

Rear air mix damper motor 
(Potentiometer input) 
<Vehicles with dual automatic 
A/C>

Rear air mix damper motor MAX 
HOT position

0.8 

− 1.2 V

23

Solar sensor input

Brightness 0 lux

5 V

Brightness 100000 lux or more

0 V

24

Ambient temperature sensor

Sensor probe temperature 25

°C 

(1.5k 

Ω)

2.1 

− 2.7 V

25

A/C pressure sensor input

Refer to 

P.55-195

Refer to 

P.55-195

26

Heat switch <Vehicles with 
dual automatic A/C>

Ignition switch: IG2
Heater switch ON

System voltage

31

Front air mix damper motor 
(COOL)

When the front air conditioner is 
moved to the COOL position 

System voltage

When the front air conditioner is 
moved to the HOT position 

0 

− 1 V

32

Front air mix damper motor 
(HOT)

When the front air conditioner is 
moved to the HOT position 

System voltage

When the front air conditioner is 
moved to the COOL position 

0 

− 1 V

33

Air outlet changeover damper 
motor (FACE)

When moving toward FACE 
position 

System voltage

When moving toward DEF position  0 

− 1 V

34

Air outlet changeover damper 
motor (DEF)

When moving toward DEF position  System voltage
When moving toward FACE 
position 

0 

− 1 V

Terminal 
No.

Check items

Check conditions

Normal conditions