Mitsubishi Lancer (4A9 engine). Manual - part 294

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-57

STEP 9. Replace the power transistor and 
recheck the trouble symptom
Check that the blower motor operates normally.

Q: Is the check result normal?

YES : 

This diagnosis is complete.

NO : 

Replace the A/C-ECU.

INSPECTION PROCEDURE 5: The Inside/Outside Air Changeover is impossible.

OUTSIDE/INSIDE AIR
SELECTION DAMPER 
CONTROL MOTOR

A/C-ECU

Outside/Inside Air Selection Damper Control Motor Circuit

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

A/C Control Panel Circuit

A/C-ECU

A/C
CONTROL
PANEL

CPU

INTERFACE
CIRCUIT

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

ACA00799

AC612706

Connectors: C-13, C-15, C-107, C-119 <LHD>

AG

C-13 (B)

C-15 (B)

C-107

C-119

AC612710

Connectors: C-13, C-15, C-107 <RHD>

AU

C-15 (B)

C-13 (B)

C-107

AC612711

Connector: C-119 <RHD>

AG

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-58

COMMENTS ON TROUBLE SYMPTOM
If the air recirculation cannot be changed by using 
the inside air/outside air changeover switch, the 
inside air/outside air changeover motor system may 
be faulty.

PROBABLE CAUSES

• Malfunction of the outside/inside air selection 

damper control motor

• Malfunction of the A/C control panel

• Damaged wiring harness or connectors

• Malfunction of the A/C-ECU

DIAGNOSIS PROCEDURE

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 15: Refer to A/
C-ECU power supply system  .

STEP 2. M.U.T.-III diagnosis code
Check that the diagnosis code related to the air con-
ditioner is not set.

Q: Is the diagnosis code set?

YES : 

Carry out the diagnosis code procedures. 

Refer to .

NO : 

Go to Step 3.

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-59

STEP 3. M.U.T.-III actuator test
Carry out the actuator test. (Refer to ).

• Item 05: In/out selection damper (Select "position 

reset".)

Q: Does the blower motor work normally?

YES : 

This diagnosis is complete.

NO : 

Go to Step 4.

STEP 4. Connector check: C-119 A/C control 
panel connector and C-15 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 C-119 
A/C control panel connector terminal No. 9 and 
C-15 A/C-ECU connector terminal No. 9. 

• Check the A/C control panel signal line for open 

or short circuit.

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Repair the wiring harness.

STEP 6. Connector check: C-13 A/C-ECU 
connector and C-107 outside/inside air selection 
damper control motor connector

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Repair the connector.

STEP 7. Check the wiring harness between C-13 
A/C-ECU connector (terminals 29, 24, 27, 25 and 
26) and C-107 outside/inside air selection damper 
control motor connector (terminals 3, 1, 4, 5 and 
2).

• Check the A/C control panel signal line and earth 

line for open or short circuit.

Q: Is the check result normal?

YES : 

Go to Step 8.

NO : 

Repair the wiring harness.

STEP 8. Replace the air outside/inside air 
circulation switching damper motor, and then 
recheck the trouble symptom.
 Check to see that the outside air/inside air circula-
tion switching damper motor operates normally.
NOTE: Whenever the motor is replaced, initialise the 
motor position by using the Actuator Test.

Q: Is the check result normal?

YES : 

This diagnosis is complete.

NO : 

Replace the A/C-ECU.

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-60

INSPECTION PROCEDURE 6: The A/C compressor does not work <Petrol engine>

A/C Compressor Assembly Circuit <Petrol engine>

 

A/C
COMPRESSOR
RELAY

A/C
COMPRESSOR
ASSEMBLY

A/C
REFRIGERANT
TEMPERATURE
SWITCH

A/C
COMPRESSOR
CLUTCH

ENGINE-ECU

RELAY
BOX

FUSIBLE
LINK

36

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

ACB02673