Mitsubishi Galant (2004+). Manual - part 723

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-31

STEP 3. Using scan tool MB991958, check actuator test 
item 10, 11, 12: air mix damper motor.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Start the engine.
(3) Use scan tool MB991958 to run the actuator test.

Item 10: air mix damper motor (MAX COOL position)
Item 11: air mix damper motor (middle position)
Item 12: air mix damper motor (MAX HOT position)

• Check that the air mixing damper control motor oper-

ates.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Does the motor operate normally?

YES : Replace the A/C-ECU. Then go to Step 7.
NO :  Go to Step 4.

STEP 4. Check A/C-ECU connectors C-09, C-10 and air 
mixing damper control motor and potentiometer connector 
C-105 for loose, corroded or damaged terminals, or 
terminals pushed back in the connector.

Q: Are A/C-ECU connectors C-09, C-10 and air mixing 

damper control motor and potentiometer connector 
C-105 in good condition?
YES : Go to Step 5.
NO :  Repair or replace the connector. Refer to GROUP 

00E, Harness Connector Inspection 

P.00E-2

. Then go 

to Step 7.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC305234

C-09 (B)

C-10 (B)

HARNESS SIDE

C-09

HARNESS SIDE

21

22

23

24

25

26

27

28

29

30

31

32

C-105

C-10

HARNESS SIDE

C-105

AF

CONNECTORS: C-09, C-10, C-105

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-32

STEP 5. Check the wiring harness between A/C-ECU 
connectors C-09 (terminal 32), C-10 (terminal 9) and air 
mixing damper control motor and potentiometer connector 
C-105 (terminals 2 and 1).

Q: Are the wiring harness between A/C-ECU connectors 

C-09 (terminal 32), C-10 (terminal 9) and air mixing 
damper control motor and potentiometer connector 
C-105 (terminals 2 and 1) in good condition?
YES : Go to Step 6.
NO :  Repair the wiring harness. Then go to Step 7.

AC305234

C-09 (B)

C-10 (B)

HARNESS SIDE

C-09

HARNESS SIDE

21

22

23

24

25

26

27

28

29

30

31

32

C-105

C-10

HARNESS SIDE

C-105

AF

CONNECTORS: C-09, C-10, C-105

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-33

STEP 6. Check the air mixing damper control motor and 
potentiometer.

CAUTION

Do not apply battery voltage when the damper is in the 
MAX COOL or MAX HOT position.
Check the air mix damper control motor by the following proce-
dures.

Q: Are the air mixing damper control motor and 

potentiometer in good condition?
YES : Replace the A/C-ECU. Then go to Step 7.
NO :  Replace the air mixing damper control motor and 

potentiometer. Then go to Step 7.

LEVER POSITION BATTERY 

CONNECTION

LEVER 
OPERATION

At the MAX COOL 
position

• Connect 

terminal 2 to the 
positive battery 
terminal

• Connect 

terminal 1 to the 
negative battery 
terminal

The lever moves 
from the MAX 
COOL position to 
the MAX HOT 
position

At the MAX HOT 
position

• Connect 

terminal 1 to the 
positive battery 
terminal

• Connect 

terminal 2 to the 
negative battery 
terminal

The lever moves 
from the MAX HOT 
position to the MAX 
COOL position

AC206296

MAX HOT POSITION

MAX COOL POSITION

1 2

4

3

5

7

6

AB

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-34

STEP 7. Recheck for diagnostic trouble code.

Check again if the DTC is set.

1. Connect scan tool MB991958 to the data link connector
2. Turn the ignition switch to the "ON" position.
3. Check if the DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the check result satisfactory?

YES : The procedure is complete.
NO :  Return to Step 1.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827