Mitsubishi 380. Manual - part 184

AUTO A/C DIAGNOSIS

HEATER, AIR CONDITIONING AND VENTILATION

55-32

STEP 5. Check the wiring harness between A/C-ECU 
connectors C-15 (terminals 16 and 20), C-16 (terminal 29) 
and air mixing damper control motor and potentiometer 
connector C-105 (terminals 5, 7 and 3).
Q: Are the wiring harness between A/C-ECU connector 

C-15 (terminals 16 and 20), C-16 (terminal 29) and air 
mixing damper control motor and potentiometer 
connector C-105 (terminals 5, 7 and 3) in good 
condition?
YES : Go to Step 6.
NO :  Repair the wiring harness. Then go to Step 7.

25DB084A

CONNECTOR: C-105

C-105

C-105

HARNESS SIDE

25DB070A

CONNECTORS: C-15, C-16

C-16 (B)

HARNESS SIDE

C-16

C-15

C-15 (B)

HARNESS SIDE

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

AUTO A/C DIAGNOSIS

HEATER, AIR CONDITIONING AND VENTILATION

55-33

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.
(1) Operate the air mixing damper control motor as described 

in the table below.

(2) Measure the resistances between connector terminals 3 

and 5, and between 3 and 7, while the air mixing damper 
control motor is running. The resistances should change 
gradually within the standard value.

Standard value: 1.7 (MAX HOT) 

− 5.0 (MAX COOL) 

k

Ω

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

25DB063A

MAX HOT POSITION

MAX COOL POSITION

1 2

4

3

5

7

6

AUTO A/C DIAGNOSIS

HEATER, AIR CONDITIONING AND VENTILATION

55-34

STEP 7. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1) Connect diagnostic tool  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.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTO A/C DIAGNOSIS

HEATER, AIR CONDITIONING AND VENTILATION

55-35

DTC B1045:  Air mixing damper control motor and potentiometer (activating system failure)

.

DTC SET CONDITION

• If the air mixing damper control motor does not 

work normally, DTC No.B1045 will be set.

.

TECHNICAL DESCRIPTION (COMMENT)

Current trouble

• The A/C-ECU, the air mixing damper control 

motor and potentiometer, or connector(s) or wir-
ing between the two may be defective.

Past trouble

• If DTC B1045 is stored as a past trouble, carry 

out diagnosis with particular emphasis on wiring 
and connector(s) between the A/C-ECU and the 
air mixing damper control motor and potentiome-
ter. If the connectors and wiring are normal, and 
obviously the ECU is the cause of the trouble, 
replace the ECU. If in doubt, do not replace the 
ECU.

TROUBLESHOOTING HINT

• Malfunction of connector.

• Malfunction of the harness.

• Malfunction of the air mixing damper control 

motor and potentiometer.

• Malfunction of the A/C-ECU.

• Refer to component locations GROUP-

70

• Refer to configuration diagrams GROUP-

80

• Refer to circuit diagrams GROUP-

90

25DB146A

C-16 (B)

C-15 (B)

C-105

CONNECTORS: C-15, C-16, C-105