Mitsubishi Grandis. Manual - part 301

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-89

Step 5. Resistance measurement at the C-103 
PTC heater connector.

(1) Disconnect the connector, and measure at the 

wiring harness side.

(2) Continuity between terminal 1 and body earth

OK: 2

Ω or less

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Go to Step 6.

Step 6. Check the wiring harness between C-103 
PTC heater connector terminal No.1 and body 
earth.

• Check the PTC heater earth 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 

P.00-5

.)

NO : 

Repair the wiring harness.

Step 7. Resistance measurement at the C-103 
PTC heater connector.

(1) Disconnect the connector, and measure at the 

wiring harness side.

(2) Continuity between terminal 3 and body earth

OK: 2

Ω or less

Q: Is the check result normal?

YES : 

Go to Step 9.

NO : 

Go to Step 8.

Step 8. Check the wiring harness between C-103 
PTC heater connector terminal No.3 and body 
earth.

• Check the PTC heater earth 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 

P.00-5

.)

NO : 

Repair the wiring harness.

AC310613

AF

Connector: C-103 <LHD>

Harness side

AC310506AQ

Connector C-106 
(Harness side)

AC310613

AF

Connector: C-103 <LHD>

Harness side

AC310613

AF

Connector: C-103 <LHD>

Harness side

AC310506AR

Connector C-106 
(Harness side)

AC310613

AF

Connector: C-103 <LHD>

Harness side

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-90

Step 9. Connector check: C-105 A/C-ECU 
connector

Q:  Is the check result normal?

YES : 

Go to Step 10.

NO : 

Repair the connector.

Step 10. Voltage measurement at C-103 PTC 
heater connector.

(1) Disconnect the connector, and measure at the 

wiring harness side.

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

(3) Disconnect A/C-ECU connector C-105 and earth 

terminal 46.

(4) Voltage between terminal 2 and body earth.

OK: System voltage

Q: Is the check result normal?

YES : 

 Go to Step 19.

NO : 

 Go to Step 11.

AC310613

AC

Connector: C-105 <LHD>

Harness side

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

AC310613

AF

Connector: C-103 <LHD>

Harness side

AC310613

AC

Connector: C-105 <LHD>

Harness side

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

AC312783

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

AC312783

Connector C-105
(Harness side)

AB

AC310507AU

Connector C-103 
(Harness side)

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-91

Step 11. Connector check: C-206 PTC heater 
relay 1 controller connector

Q: Is the check result normal?

YES : 

Go to Step 12.

NO : 

Repair the connector.

Step 12. Check the PTC heater switch relay 1 
continuity.

 Refer to 

P.55-196

.

Q: Is the PTC heater switch relay 1 in good condition?

YES : 

Go to Step 13.

NO : 

Replace the PTC heater switch relay 1.

Step 13. Voltage measurement at C-206 PTC 
heater relay 1 connector.

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

side.

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

(3) Voltage between terminal 3 and body earth.

OK: System voltage

Q: Is the check result normal?

YES : 

 Go to Step 15.

NO : 

 Go to Step 14.

AC310623

Connector: C-206 <LHD>

AE

3

4

5

1

2

Junction block side

Junction block (Front view)

AC310623

Connector: C-206 <LHD>

AE

3

4

5

1

2

Junction block side

Junction block (Front view)

AC310507

3

4

5

1

2

Connector C-206 
(Junction block side)

AV

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-92

Step 14. Check the wiring harness between C-206 
PTC heater relay 1 connector terminal No.3 and 
the ignition switch (IG2).

NOTE: 

Prior to the wiring harness inspection, check junction 
block connectors C-202, C-203 and joint connector 
C-32, and repair if necessary.

• Check the PTC heater relay 1 earth 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 

P.00-5

.)

NO : 

Repair the wiring harness.

Step 15. Voltage measurement at C-206 PTC 
heater relay 1 connector.

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

side.

(2) Voltage between terminal 4 and body earth.

OK: System voltage

Q: Is the check result normal?

YES : 

 Go to Step 17.

NO : 

 Go to Step 16.

AC310624

Connectors: C-202, C-203, C-206 <LHD>

AG

3

4

5

1

2

Junction block side

Junction block (Front view)

C-206

C-202

C-206

Harness side

C-202

C-203

Harness side

C-203

10

1

6

14

5

12

13

4

11

7

2

3

8

9

AC310613

AG

Connector: C-32 <LHD>

AC310623

Connector: C-206 <LHD>

AE

3

4

5

1

2

Junction block side

Junction block (Front view)

AC310507

3

4

5

1

2

Connector C-206 
(Junction block side)

AW