Mitsubishi L200. Manual - part 881

TROUBLESHOOTING

AUTOMATIC AIR CONDITIONER

55B-53

STEP 8. Check the wiring harness between A-21X 
A/C compressor relay connector terminal No.4 
and the fusible link (20).

AC510163

AE

Connector: A-21X

Relay box side

AC509975AW

Harness side

Connector: A-115

NOTE: Prior to the wiring harness inspection, check 
intermediate connector A-115 repair if necessary.

• Check the A/C compressor relay power supply 

line for open circuit.

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00, How to 
Cope with Intermittent Malfunction ).

NO : 

Repair the wiring harness.

STEP 9. Check the wiring harness between A-21X 
A/C compressor relay connector terminal No.3 
and A-33 A/C compressor connector terminal 
No.1.

AC510163

AE

Connector: A-21X

Relay box side

AC509975AV

A-33 Harness side

Connectors: A-27, A-28, A-33 

A-33 (B)

A-28 (B)

A-28

A-27 (B)

A-27 

NOTE: Prior to the wiring harness inspection, check 
intermediate connector A-28 and A-27, and repair if 
necessary.

• Check the A/C compressor relay power supply 

line for open circuit.

Q: Is the check result normal?

YES : 

 Go to Step 10.

NO : 

Repair the wiring harness.

TROUBLESHOOTING

AUTOMATIC AIR CONDITIONER

55B-54

STEP 10. Check the wiring harness between A-
21X A/C compressor relay connector terminal 
No.2 and C-105 engine-ECU connector terminal 
No.40.

AC510163

AE

Connector: A-21X

Relay box side

AC509613 CD

Harness side

C-105 (B)

Connector: C-105 <LHD>

35

40

41

42

1817

38

39

15

16

14

3736

12

13

11

32

8

3433

9

10

30

31

7 6

29

5

4

28

3

27

2

26

1

25

19
43

2120

22

23

46

47

4544

24
48

76

52

86

62

63

64

65

66

67

68

69

70

71

72

92

95

96

93

94

89

90

91

8887

53

54

55

56

57

58

59

60

61

83

8584

8281

78

79

80

77

49

50

51

74

75

73

AC509930 CA

C-105 (B)

Connector: C-105 <RHD>

Harness side

35

40

41

42

1817

38

39

15

16

14

3736

12

13

11

32

8

3433

9

10

30

31

7 6

29

5

4

28

3

27

2

26

1

25

19
43

2120

22

23

46

47

4544

24
48

76

52

86

62

63

64

65

66

67

68

69

70

71

72

92

95

96

93

94

89

90

91

8887

53

54

55

56

57

58

59

60

61

83

8584

8281

78

79

80

77

49

50

51

74

75

73

• Check the A/C compressor power supply line for 

open circuit.

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00, How to 
Cope with Intermittent Malfunction ).

NO : 

Repair the wiring harness.

STEP 11. Check the magnetic clutch operation.
 Refer to .

Q: Can the sound of the magnetic clutch (click) be 

heard?
YES : 

Go to Step 12.

NO : 

Replace the compressor magnet clutch. 

STEP 12. Check the refrigerant level.
 Refer to .

Q: Is the refrigerant level correct?

YES : 

Go to Step 13.

NO : 

Correct the refrigerant level (Refer to ).

STEP 13. Replace the A/C-ECU, and then recheck 
the trouble symptom
 Check that the compressor works normally.

Q: Is the check result normal?

YES : 

This diagnosis is complete.

NO : 

Replace the engine-ECU.

TROUBLESHOOTING

AUTOMATIC AIR CONDITIONER

55B-55

Inspection Procedure 6: The rear window defogger does not work <Vehicles without rear panel power 
window>

Rear Window Defogger Circuit

REAR WINDOW
DEFOGGER RELAY

REAR WINDOW
DEFOGGER SWITCH

REAR WINDOW
DEFOGGER 

A/C-SWITCH
MODULE

FUSIBLE
LINK

IGNITION
SWITCH (IG2)

20

Wire colour code
B : Black     LG : Light green     G : Green     L : Blue     W : White     Y : Yellow     SB : Sky blue
BR : Brown     O : Orange     GR : Grey     R : Red     P : Pink     V : Violet     PU : Purple

AC900630

COMMENTS ON TROUBLE SYMPTOM
If the rear window defogger does not operate when 
the rear window defogger switch is turned on, the 
rear window defogger relay system may be defec-
tive.

PROBABLE CAUSES

• Malfunction of the automatic A/C control panel (A/

C-ECU)

• Malfunction of the rear window defogger relay

• Damaged the wiring harness or connectors

• Malfunction of the rear window defogger

TROUBLESHOOTING

AUTOMATIC AIR CONDITIONER

55B-56

DIAGNOSIS PROCEDURE

STEP 1. Check the A/C operation.

Q: Do the A/C work normally?

YES : 

Go to Step 2.

NO : 

Refer to Inspection procedure 1 "Cool air 
does not come 

P.55B-23

."