Mitsubishi Lancer Evolution IX. Manual - part 545

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-53

STEP 19. Check the wiring harness between C-36 
A/C-ECU connector terminal No.2 and C-34 
blower linear controller connector terminal No.5.

• Check the communication line for open or short 

circuit.

Q: Is the check result normal?

YES : 

Replace the A/C control panel (A/C-ECU) or 

the blower motor (blower linear controller).

NO : 

Repair the wiring harness.

AC504617AC

Connector: C-34 <LHD>

Harness side

AC504624AB

Connectors: C-34, C-36 <RHD>

Harness side

C-34

C-36 (B)

C-34

C-36

AC504622AB

Connector: C-36 <LHD>

Harness side

C-36 (B)

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-54

Inspection Procedure 5: The Blower Air Volume cannot be changed.

COMMENTS ON TROUBLE SYMPTOM

If the blower air volume can not be changed when 
the blower switch is operated, the circuit between 
blower motor (blower linear controller) and A/C-ECU 
may be defective.

POSSIBLE CAUSES

• Blower motor (blower linear controller)

• Damaged the wiring harness or connectors

• Malfunction of the automatic A/C control panel 

(A/C-ECU)

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-II/III actuator test
Carry out the actuator test.

• Items 01, 02, 03, 04: Blower motor

Q: Does the blower motor work normally? 

YES : 

Replace the automatic A/C control panel 

(A/C-ECU)

NO : 

Go to Step 2.

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

Blower Motor Circuit

BLOWER
RELAY

A/C-ECU

BLOWER MOTOR
(BLOWER
 LINEAR
 CONTROLLER)

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-55

STEP 2. Connector check: C-36 A/C-ECU 
connector and C-34 blower linear controller 
connector

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair the connector.

STEP 3. Check the wiring harness between C-36 
A/C-ECU connector terminal No.2 and C-34 
blower linear controller connector terminal No.5.

• Check the communication line for open or short 

circuit.

Q: Is the check result normal?

YES : 

Replace the automatic A/C control panel 

(A/C-ECU) or the blower motor (blower 
linear controller).

NO : 

Repair the wiring harness.

AC504617AC

Connector: C-34 <LHD>

Harness side

AC504624AB

Connectors: C-34, C-36 <RHD>

Harness side

C-34

C-36 (B)

C-34

C-36

AC504622AB

Connector: C-36 <LHD>

Harness side

C-36 (B)

AC504617AC

Connector: C-34 <LHD>

Harness side

AC504624AB

Connectors: C-34, C-36 <RHD>

Harness side

C-34

C-36 (B)

C-34

C-36

AC504622AB

Connector: C-36 <LHD>

Harness side

C-36 (B)

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-56

Inspection Procedure 6: When sunlight intensity changes, blower air temperature does not Change.

CIRCUIT OPERATION

When the blower air temperature can not be 
changed even if the preset temperature is changed, 
the sensors may be defective.

PROBABLE CAUSES

• Malfunction of the photo sensor

• Damaged the wiring harness or connectors

• Malfunction of the A/C-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check the rear window defogger and 
outside/inside air selection damper control motor 
operation.

Q: Do the rear window defogger and outside/inside air 

selection damper control motor work normally?
YES : 

Go to Step 2.

NO : 

Refer to Inspection procedure 9 
"Malfunction of the A/C-ECU power supply 
system 

P.55-73

."

STEP 2. M.U.T.-II/III diagnosis code
On completion, check that the diagnosis code is not 
reset.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Carry the diagnosis code procedures. Refer 
to 

P.55-5

.

STEP 3. M.U.T.-II/III data list

• Item 25: Photo sensor

OK: Check that the volume of insolation takes 
inverse proportion with the M.U.T.-II/III displayed 
voltage.

Q: Is the check result normal?

YES : 

Replace the automatic A/C control panel 

(A/C-ECU).

NO : 

Go to Step 4.

Photo Sensor 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

A/C-ECU

PHOTO SENSOR