Mitsubishi L200. Manual - part 861

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-60

(2) Turn the ignition switch to the "ON" position.

AC310507

Connector C-141X
(Junction block side)

JZ

(3) Voltage between terminal 3 and body earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 21.

NO : 

Go to Step 20.

STEP 20. Check the wiring harness between A-
141X PTC heater relay 2 connector terminal No.3 
and the ignition switch (IG2).

AC509815

A-141X

Connector: A-141X

AD

Relay box side

NOTE: 

AC509975AH

Connector: A-28

A-28 (B)

AC509613AW

Connector: C-148 <LHD>

AC509934 AX

Connectors: C-207, C-210 <LHD>

Harness side

C-207

C-210

Junction block (Front view)

Harness side

C-207

C-210

Prior to the wiring harness inspection, check junction 
block connectors C-207, C-210, intermediate con-
nector A-28 and C-148, and repair if necessary.

• Check the PTC heater relay 2 power supply line 

for open circuit.

Q: Is the check result normal?

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-61

YES : 

The trouble can be an intermittent 

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

NO : 

Repair the wiring harness.

STEP 21. Voltage measurement at A-141X PTC 
heater relay 2 connector.

AC509815

A-141X

Connector: A-141X

AD

Relay box side

(1) Remove the relay, and measure at the relay block 

side.

AC310507

Connector C-141X
(Junction block side)

KA

(2) Voltage between terminal 2 and body earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 23.

NO : 

Go to Step 22.

STEP 22. Check the wiring harness between A-
141X PTC heater relay 2 connector terminal No.2 
and the fusible link (25).

AC509815

A-141X

Connector: A-141X

AD

Relay box side

• Check the PTC heater relay 2 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 23. Check the wiring harness between A-
141X PTC heater relay 2 connector terminal No.1 
and C-105 engine-ECU connector terminal No.41.

AC509815

A-141X

Connector: A-141X

AD

Relay box side

AC509613CE

Connectors: C-105, C-148 <LHD>

C-148

C-148

C-105

Harness side

C-105 (B)

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

NOTE: Prior to the wiring harness inspection, check 
intermediate connector C-148, and repair if neces-
sary.

• Check the PTC heater relay 2 earth line for open 

and short circuit.

Q: Is the check result normal?

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-62

YES : 

Go to Step 24.

NO : 

Repair the wiring harness.

STEP 24. Check the wiring harness between A-
141X PTC heater relay 2 connector terminal No.4 
and C-150 PTC heater connector terminal No.2.

AC509815

A-141X

Connector: A-141X

AD

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

• Check the PTC heater 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 25. Connector check: C-05 A/C switch 
module controller connector

AC509611AV

Connector: C-05 <LHD>

Harness side

Q: Is the check result normal?

YES : 

Go to Step 26.

NO : 

Repair the connector.

STEP 26. Check the wiring harness between C-05 
A/C switch module connector terminal No.1 and 
C-105 engine-ECU connector terminal No.35.

AC509611AV

Connector: C-05 <LHD>

Harness 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

NOTE: Prior to the wiring harness inspection, check 
intermediate connector C-52, and repair if necessary.

•

AC509613AV

Connector: C-52 <LHD>

Check the A/C control module input line for open and 

short circuit.

Q: Is the check result normal?

YES : 

Go to Step 27.

NO : 

Repair the wiring harness.

STEP 27. Check the trouble symptom
 Check that the PTC heater works normally.

Q: Is the check result normal?

YES : 

This diagnosis is complete.

NO : 

Replace the engine-ECU.

ON-VEHICLE SERVICE

HEATER, AIR CONDITIONER AND VENTILATION

55A-63

CHECK AT A/C EVAPORATOR AIR 
OUTLET THERMISTOR TERMINALS

M1552010302738

AC501416

<C-21>

AD

Terminal No.

Check items

Check conditions

Normal conditions

1

Earth

Always

1 V or less

2

Power supply

IG2: ON

System voltage

4

Output from A/C 
evaporator air outlet 
thermistor to engine-
ECU

Blower switch: 4
Temperature control dial: MAX cool
evaporator temperature of the back: 
3

°C or higher

System voltage

Other than above

1 V or less

5

Communication with 
A/C switch module

Temperature control dial: MAX cool System voltage

6

Communication with 
A/C switch module

Temperature control dial: MAX cool System voltage

ON-VEHICLE SERVICE

A/C COMPRESSOR DRIVE BELT 
TENSION CHECK AND ADJUSTMENT

M1552001001327

Refer to GROUP 11A, On-vehicle Service 

− A/C 

compressor drive belt tension check and adjustment 
.

A/C COMPRESSOR CLUTCH TEST

M1552008500591

1. Disconnect the A/C compressor clutch connector 

to the A/C compressor clutch.

AC407428

A/C compressor clutch connector

AB

2. Connect positive battery voltage directly to the 

connector for the A/C compressor clutch.

3. If the A/C compressor clutch is normal, there will 

be a "click." If the pulley and armature do not 
make contact ("click"), there is a malfunction.

CHARGING AND DISCHARGING

M1552022200215

Use the refrigerant recovery unit to discharge refrig-
erant gas front the system.
NOTE: Refer to the Refrigerant Recovery and Recy-
cling Unit instruction Manual for operation of the unit.

CHECK THE REFRIGERANT LEVEL

M1552021700165

Remove the refrigerant by the flon reclaim machine 
and replenish the specified quantity of refrigerant.
NOTE: Refer to the Refrigerant Recovery and Recy-
cling Unit instruction Manual for operation of the unit.

REFILLING OF OIL IN THE A/C SYSTEM

M1552020000259

Too little oil will provide inadequate compressor lubri-
cation and cause a compressor failure. Too much oil 
will increase discharge air temperature.