Mitsubishi Grandis. Manual - part 318

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-157

Step 11. Connector check: D-10 rear blower 
motor

Q:  Is the check result normal?

YES : 

Go to Step 12.

NO : 

Repair the connector.

Step 12. Check the rear blower motor

 Refer to 

P.55-217

.

Q: Is the check result normal?

YES : 

Go to Step 13.

NO : 

Replace the rear blower motor.

Step 13. Check the wiring harness between D-10 
rear blower motor connector terminal No.1 and 
C-15 intermediate connector terminal No.1.

• Check the rear blower relay power supply line for 

open circuit.

Q: Is the check result normal?

YES : 

Go to Step 14.

NO : 

Repair the wiring harness.

Step 14. Connector check: D-11 rear power 
transistor connector

Q: Is the check result normal?

YES : 

Go to Step 15.

NO : 

Repair the connector.

Step 15. Resistance measurement at the D-11 
rear power transistor connector.

(1) Disconnect the connector, and measure at the 

wiring harness side.

(2) Continuity between terminal 2 and body earth

OK: 2

Ω or less

Q: Is the check result normal?

YES : 

Go to Step 17.

NO : 

Go to Step 16.

AC310207

AD

Harness side

Connector: D-10

AC310615

AD

Connector: C-15 <LHD>

AC310207

AD

Harness side

Connector: D-10

AC310207

AC

Harness side

Connector: D-11

AC310207

AC

Harness side

Connector: D-11

AC310506

Connector D-11 
(Harness side)

AT

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-158

Step 16. Check the wiring harness between D-11 
rear power transistor terminal No.2 and body 
earth.

• Check the blower linear controller 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 17. Connector check: C-104 A/C-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 18.

NO : 

Repair the connector.

Step 18. Check the wiring harness between D-11 
rear power transistor connector terminal No.4 
and D-10 rear blower motor connector terminal 
No.2.

• Check the blower linear controller earth line for 

open circuit.

Q: Is the check result normal?

YES : 

Go to Step 19.

NO : 

Repair the wiring harness.

AC310207

AC

Harness side

Connector: D-11

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

AC310208

AB

Harness side

Connectors: D-10, D-11

D-10

D-11

D-10

Harness side

D-11

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-159

Step 19. Check the wiring harness between D-11 
rear power transistor connector (terminal 1 and 
3) and D-10 A/C-ECU connector (terminal 60 and 
59).

NOTE: 

Prior to the wiring harness inspection, check 
intermediate connector C-15, and repair if necessary.

• Check the blower linear controller earth line for 

open circuit.

Q: Is the check result normal?

YES : 

Go to Step 20.

NO : 

Repair the wiring harness.

Step 20. Replace the rear power transistor and 
recheck the trouble symptom

Check that the rear blower motor should work 
normally.

Q: Is the check result normal?

YES : 

This diagnosis is complete.

NO : 

Replace the A/C-ECU.

AC310208

AB

Harness side

Connectors: D-10, D-11

D-10

D-11

D-10

Harness side

D-11

AC310615

AD

Connector: C-15 <LHD>

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-160

INSPECTION PROCEDURE 23: Rear blower motor power supply system <RHD>

CIRCUIT OPERATION

If the rear blower motor does not operate, the rear 
blower motor circuit system may be defective.

POSSIBLE CAUSES

• Malfunction of rear blower relay

• Malfunction of rear blower motor

• Malfunction of rear power transistor 

• Malfunction of the A/C-ECU

• Damaged harness wires and connectors

FUSIBLE
LINK

30

IGNITION
SWITCH (IG2)

FUSE BOX

REAR
BLOWER
RELAY

REAR
BLOWER
MOTOR

REAR
POWER
TRANSISTOR

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 blower motor circuit