Mitsubishi Montero (2002-2004). Manual - part 42

REAR AIR CONDITIONING DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-31

DIAGNOSIS

STEP 1. Check the rear heater switch (temperature control 
switch).
Connect the tester between the connector terminal number 3 
and number 5, between the terminal number 5 and number 13 
and make sure that the resistance value changes slowly within 
the standard value.

Standard value: 0 

− 3 kΩ

Q: Is the check result normal?

YES :  Go to Step 2.
NO :  Replace the rear air-conditioner switch.

AC204170

CONNECTOR : D-30

BC

AC204171

CONNECTOR : D-112

AU

AC204176

CONNECTORS : E-01, E-06, E-12

BP

E-12

E-01

E-06

AC204175

CONNECTOR : E-21

AJ

AC204179

CONNECTORS : G-23, G-25

AZ

G-23

G-25

AC204698 AT

G-25-1

G-25-2

CONNECTORS : G-25-1, G-25-2

AC205161

1
7

2
8

10 11

5

13

6

14

12

4

9

3

REAR AIR CONDITIONING DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-32

STEP 2. Measure the resistance at rear heater control unit 
connector E-01.
(1) Disconnect rear heater control unit connector E-01, and 

measure at the wiring harness side.

(2) Turn the rear fan switch to the "ON" position.
(3) Turn the rear fan control switch to the "OFF" position.

(4) Measure the resistance between terminal 13 and ground.

• The measured value should be 2 ohms or less.

Q: Does the measured resistance value correspond with 

this range?
YES :  Go to Step 5.
NO :   Go to Step 3.

STEP 3. Check rear heater control unit connector E-01 and 
rear fan control switch connector E-12 for damage.
Q: Is rear heater control unit connector E-01 and rear fan 

control switch connector E-12 in good condition?
YES : Go to Step 4.
NO :  Repair or replace the connector. Refer to GROUP 

00E, Harness Connector Inspection 

P.00E-2

. Check 

that the air conditioning works normally.

AC204176

CONNECTOR : E-01

AU

HARNESS SIDE

7

8

3

10 9

2

4

11

1312

5

14

6

1

AC204738

7

8

3

10 9

2

4

11

1312

5

14

6

1

CG

HARNESS SIDE : E-01

AC204194

CONNECTORS : E-01, E-12

AL

E-01

E-01

E-12

HARNESS SIDE

E-12

HARNESS SIDE

7

8

3

10 9

2

4

11

1312

5

14

6

1

1
4

2

3

5

6

REAR AIR CONDITIONING DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-33

STEP 4. Check the wiring harness between rear heater 
control unit connector E-01 (terminal 13) and rear fan 
control switch connector E-12 (terminal 1).
NOTE: Also check intermediate connector E-06. If intermediate 
connector E-06 is damaged, repair or replace the connector as 
described in GROUP 00E, Harness Connector Inspection 

P.00E-2

.

Q: Is the wiring harness between rear heater control unit 

connector E-01 (terminal 13) and rear fan control switch 
connector E-12 (terminal 1) in good condition?
YES : Check that the rear air conditioning works normally.
NO :  Repair the wiring harness. Check that the rear air 

conditioning works normally.

STEP 5. Check rear heater control unit connector E-01 and 
rear heater switch E-21 for damage.
Q: Is rear heater control unit connector E-01 and rear 

heater switch E-21 in good condition?
YES : Go to Step 6.
NO :  Repair or replace the connector. Refer to GROUP 

00E, Harness Connector Inspection 

P.00E-2

. Check 

that the rear air conditioning works normally.

AC204194

CONNECTORS : E-01, E-06, E-12

AZ

E-01

E-01

E-12

HARNESS SIDE

HARNESS SIDE

E-12

E-06

E-06

7

8

3

10 9

2

4

11

1312

5

14

6

1

1
4

2

3

5

6

22

2021

10

9

8

1718

6 7

19

1415

4 5

1112

1 2 3

13

16

AC204176

CONNECTOR : E-01

AU

HARNESS SIDE

7

8

3

10 9

2

4

11

1312

5

14

6

1

AC204175

CONNECTOR : E-21

AF

HARNESS SIDE

FLOOR 
COSOLE

1
7

2
8

10

11

5

13

6

14

12

4

9

3

REAR AIR CONDITIONING DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-34

STEP 6. Check the wiring harness between rear heater 
control unit connector E-01 (terminal 3, 4 and 8) and rear 
heater switch connector E-21 (terminal 5, 3 and 13).

NOTE: Also check intermediate connector D-112. If intermedi-
ate connector D-112 is damaged, repair or replace the connec-
tor as described in GROUP 00E, Harness Connector 
Inspection 

P.00E-2

.

Q: Is the wiring harness between rear heater control unit 

connector E-01 (terminal 3, 4 and 8) and rear heater 
switch connector E-21 (terminal 5, 3 and 13) in good 
condition?
YES : Go to Step 7.
NO :  Repair the wiring harness. Check that the rear air 

conditioning works normally.

AC204176

CONNECTOR : E-01

AU

HARNESS SIDE

7

8

3

10 9

2

4

11

1312

5

14

6

1

AC204175

CONNECTOR : E-21

AF

HARNESS SIDE

FLOOR 
COSOLE

1
7

2
8

10

11

5

13

6

14

12

4

9

3

AC204171 AL

CONNECTOR : D-112

2 3

27

32

28

33

16

15

4 5

19

18

29

17

34

7 8

35

22

21

9 10

30

36

31

37

25

24

23

6

20

1

14

26

11

13

12

38