Mitsubishi Grandis. Manual - part 294

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-61

Step 6. Check the wiring harness between C-12 
front power transistor connector 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 7. Connector check: C-106 A/C-ECU 
controller connector

Q: Is the check result normal?

YES : 

Go to Step 8.

NO : 

Repair the connector.

AC310615

AG

Connector: C-12 <LHD>

Harness side

AC310628AG

Connector: C-12 <RHD>

Harness side

AC310613

AB

Connector: C-106 <LHD>

Harness side

AC310631AB

Connectors: C-106 <RHD>

Harness side

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-62

Step 8. Check the wiring harness between C-106 
A/C-ECU connector (terminals 2 and 3) and C-12 
front power transistor controller connector 
(terminals 3 and 1).

• Check the blower linear controller power supply 

line for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 9.

NO : 

Repair the wiring harness.

Step 9. Replace the front power transistor and 
check the trouble symptom

 Check that the front blower motor operates normally.

Q: Does the blower motor work normally? 

YES : 

This diagnosis is complete.

NO : 

Replace the automatic air conditioner 
control panel (A/C-ECU)

STEP 10. Check the trouble symptom

 Check that the front blower motor operates normally.

Q: Is the check result normal?

YES : 

This diagnosis is complete.

NO : 

Replace the A/C-ECU.

AC310615

AG

Connector: C-12 <LHD>

Harness side

AC310628AG

Connector: C-12 <RHD>

Harness side

AC310613

AB

Connector: C-106 <LHD>

Harness side

AC310631AB

Connectors: C-106 <RHD>

Harness side

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-63

INSPECTION PROCEDURE 5: The inside/outside air changeover is impossible. <LHD>

COMMENTS ON TROUBLE SYMPTOM

When inside air cannot be changed to outside air 
vice versa even if its changeover switch is on, the 
outside/inside air selection damper control motor 
system may be defective.

POSSIBLE CAUSES

• Malfunction of the outside/inside air selection 

damper control motor

• Damaged the wiring harness or connectors

• Malfunction of the automatic air conditioner 

control panel (A/C-ECU)

DIAGNOSIS

STEP 1. Check the operation of the heater control 
panel

Check that the A/C switch, rear window defogger 
switch and air volume control dial can operate.

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

INSPECTION PROCEDURE 26: Refer to 
A/C-ECU power supply system 
<LHD>

P.55-174

  .

Step 2. MUT-III actuator test

Carry out the actuator test. (Refer to 

P.55-186

.)

• Item 30: In/out changeover dumper: Recirc

• Item 31: In/out changeover dumper: Fresh

Q: Does the blower motor work normally?

YES : 

Replace the automatic air conditioner 

control panel (A/C-ECU)

NO : 

Go to Step 3.

A/C-ECU

IGNITION
SWITCH (IG2)

OUTSIDE/INSIDE AIR
SELECTION DAMPER
CONTROL MOTOR

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

Outside/Inside Air Selection Damper Control Motor Circuit

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-64

Step 3. Connector check: C-10 outside/inside air 
selection damper control motor connector

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Repair the connector.

Step 4. Voltage measurement at C-10 
outside/inside air selection damper control motor 
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 6.

NO : 

Go to Step 5.

AC310615

AH

Harness side

Connector: C-10 <LHD>

AC310615

AH

Harness side

Connector: C-10 <LHD>

AC310507AR

Connector C-10 
(Harness side)