Mitsubishi Montero (2004+). Manual — part 648

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-81

STEP 1. Using scan tool MB991958, check actuator test
item 01, item 02, item 03 and item04: Blower 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.
Carry out the actuator test.
Item 01, 02, 03 and 04: Blower motor
Q: Do the check results show "Stop" (01 activated), "low

speed" (02 activated), "medium speed" (03 activated),
and "high speed" (04 activated)?
YES : Go to Step 4.
NO : Go to Step 2.

STEP 2. Check A/C-ECU connector D-23 and heater blower
controller unit connector D-17 for damage.

Q: Is A/C-ECU connector D-23 and heater blower controller

unit D-17 in good condition?
YES : Go to Step 3.
NO : Repair or replace the connector. Refer to GROUP

00E, Harness Connector Inspection

P.00E-2

. The

blower motor should operate normally.

AC307591 AB

MB991911

DATA LINK

CONNECTOR

MB991824

MB991827

AC204171

CONNECTOR : D-17

AP

1

2

3

4

HARNESS
SIDE

AC204170

CONNECTOR : D-23

D-23(B)

D-23(B)

CP

HARNESS
SIDE

1

3

4

2

12

1413

11

6

7

8

10 9

18

19

20

16

17

5

15

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-82

STEP 3. Check the wiring harness between A/C-ECU
connector D-23 (terminal 10) and heater blower controller
unit connector D-17 (terminal 3).

Q: Is the wiring harness between A/C-ECU connector D-23

(terminal 10) and heater blower controller unit
connector D-17 (terminal 3) in good condition?
YES : Go to Step 4.
NO : Repair the wiring harness. The blower motor should

operate normally.

STEP 4. Check the flexible flat cable (FFC).

(1) The FCC is connected to the automatic air conditioning

control panel assembly. Check that the FCC connection is
contaminated with foreign material or loose (Refer to

P.55B-142

).

(2) There should be continuity across the FFC terminals.
Q: Is the FFC normal?

YES : Go to Step 5.
NO : Repair the FFC (Refer to

P.55B-142

). The blower

motor should operate normally.

AC204171

CONNECTOR : D-17

AP

1

2

3

4

HARNESS
SIDE

AC204170

CONNECTOR : D-23

D-23(B)

D-23(B)

CP

HARNESS
SIDE

1

3

4

2

12

1413

11

6

7

8

10 9

18

19

20

16

17

5

15

AC205264AB

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-83

STEP 5. Check the blower switch.

Follow the table below to check the blower switch for continuity.

Q: Is the check result normal?

YES : Replace the A/C-ECU. The blower motor should

operate normally.

NO : Replace the automatic air-conditioning control panel.

The blower motor should operate normally.

SWITCH
POSITION

TESTER CONNECTION SPECIFIED

CONDITION

OFF

9

− 10

Less than 2 ohms

AUTO

8

− 9, 9 − 10

Less than 2 ohms

1

8

− 9

Less than 2 ohms

2

6

− 9, 8 − 9

Less than 2 ohms

3

6

− 9, 8 − 9, 9 − 10

Less than 2 ohms

4

6

− 9, 9 − 10

Less than 2 ohms

5

6

− 9

Open circuit

6

4

− 9, 6 − 9

Less than 2 ohms

7

4

− 9, 6 − 9, 9 − 10

Less than 2 ohms

8

4

− 9, 6 − 9, 8 − 9, 9 − 10 Less than 2 ohms

AC205403

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

AC

AC205260

OFF

AUTO

8

7

6

5

4

3

2

1

AB

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-84

INSPECTION PROCEDURE 6: Air Outlet Vent cannot be Changed.

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B (Vehicles without

CAN communication system)

A/C-ECU

MOTOR DRIVE
CIRCUIT

MODE SELECTION
DAMPER CONTROL
MOTOR AND
POTENTIOMETER

Outlet Air Changeover Damper Motor Circuit

AC204170

CONNECTORS : D-22, D-23

EE

D-23(B)

D-22(B)