Mitsubishi Grandis. Manual - part 315

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-145

Step 4. Connector check: C-106 A/C-ECU 
connector

Q:  Is the check result normal?

YES : 

Go to Step 5.

NO : 

Repair the connector.

Step 5. Check the wiring harness between A-37 
A/C pressure sensor connector (terminals 2, 1 
and 3) and C-106 A/C-ECU connector (terminals 
25, 14 and 1).

NOTE: Prior to the wiring harness inspection, check 
intermediate connector C-125, and repair if 
necessary.

• Check the input line for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Repair the wiring harness.

STEP 6. Recheck the trouble symptom

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 : 

Replace the A/C-ECU.

AC310631AB

Connectors: C-106 <RHD>

Harness side

AC310396

Connector: A-37 <RHD>

Harness side

AI

A-37 (B)

AC310631AB

Connectors: C-106 <RHD>

Harness side

AC310628AB

Connector: C-125 <RHD>

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-146

INSPECTION PROCEDURE 20: Rear fan switch system <LHD>

COMMENTS ON TROUBLE SYMPTOM

If a rear fan switch signal is not set to the A/C-ECU, 
the rear fan switch or the rear fan switch circuit 
system may be defective.

POSSIBLE CAUSES

• Malfunction of the rear fan switch

• Malfunction of the A/C-ECU

• Damaged harness wires and connectors

DIAGNOSIS

Step 1. Connector check: C-19 rear fan switch

Q:  Is the check result normal?

IGNITION
SWITCH (IG2)

REAR
FAN
SWITCH

A/C-ECU

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

Rear Fan Switch Circuit

AC310613

AL

Connector: C-19 <LHD>

Harness side

C-19 (GR)

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-147

YES : 

Go to Step 2.

NO : 

Repair the connector.

Step 2. Check the rear fan switch

 Refer to 

P.55-199

.

Q:  Is the check result normal?

YES : 

Go to Step 3.

NO : 

Replace the rear fan switch.

Step 3. Voltage measurement at C-19 rear fan 
switch connector.

(1) Disconnect the connector, and measure at the 

wiring harness side.

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

(3) Measure the voltage between terminal 1 and 

body earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Go to Step 4.

Step 4. Check the wiring harness between C-19 
rear fan switch connector terminal No.1 and the 
ignition switch (IG2).

NOTE: 

Prior to the wiring harness inspection, check joint 
connector C-31 and junction block connector C-205 
and C-202, and repair if necessary.

• Check the rear fan switch power supply line for 

open circuit.

Q: Is the check result normal?

AC310613

AL

Connector: C-19 <LHD>

Harness side

C-19 (GR)

AC310507

Connector C-19 
(Harness side)

BD

AC310614

BE

Connectors: C-19, C-31 <LHD>

C-31

C-19 (GR)

C-31

C-19

Harness side

AC310624

Connectors: C-202, C-205 <LHD>

AF

Junction block (Front view)

C-205

C-202

C-205

Harness side

C-202

Harness side

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-148

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 5. Connector check: C-104 A/C-ECU 
connector.

Q:  Is the check result normal?

YES : 

Go to Step 6.

NO : 

Repair the connector.

Step 6. Check the wiring harness between C-19 
rear fan switch connector terminal No.2 and 
C-104 A/C-ECU connector terminal No.71.

• Check the rear fan switch activating lines for 

open or short circuit.

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Repair the wiring harness.

STEP 7. Recheck the trouble symptom

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 : 

Replace the A/C-ECU.

AC310613

AK

Connector: C-104 <LHD>

Harness side

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

AC310614

BF

Connectors: C-19, C-104 <LHD>

C-104

C-19 (GR)

C-104

C-19

Harness side

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72