Mitsubishi Galant 9G. Manual — part 250

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-76

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).

NOTE: Also check joint connector C-03 for loose, corroded, or
damaged terminals, or terminals pushed back in the connector.
If joint connector C-03 is damaged, repair or replace the con-
nector as described in GROUP 00E, Harness Connector
Inspection

P.00E-2

.

Q: Are 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) in good
condition?
YES : Go to Step 6.
NO : Repair the wiring harness. Then go to Step 7.

AC305234

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

AI

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

C-105

C-105

HARNESS SIDE

AC305231BP

CONNECTOR: C-03

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-77

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 : Repair the A/C-ECU. 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-78

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.

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

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

A/C-ECU

AIR MIXING
DAMPER CONTROL
MOTOR AND
POTENTIOMETER

MOTOR
DRIVE
CIRCUIT

Air Mixing Control Motor Circuit

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-79

.

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.

AC305233

C-15 (B)

BF

C-105

CONNECTORS: C-15, C-105