Mitsubishi Lancer (4A9 engine). Manual - part 291

 

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Mitsubishi Lancer (4A9 engine). Manual - part 291

 

 

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-45

STEP 2. M.U.T.-III actuator test
Carry out the actuator test. (Refer to ).

• Item 08: Air outlet c/o damper: (Select "position 

reset".)

Q: Is the check result normal?

YES : 

This diagnosis is complete.

NO : 

Go to Step 3.

STEP 3. Connector check: C-108 mode selection 
damper control motor connector and C-59 heater 
control unit connector

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Repair the connector concerned.

STEP 4. Check the wiring harness wires between 
C-108 mode selection damper control motor 
connector (terminals 1, 4, 5, 2 and 3) and C-59 
heater control unit connector (terminals 33, 30, 
32, 31 and 29).

• Check the input line for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Repair the wiring harness.

STEP 5. Replace the mode selection damper 
control motor, and recheck the trouble symptom.
Check that the air outlets can be changed.
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 heater control unit.

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-46

INSPECTION PROCEDURE 7: Blower motor power supply system

Blower Motor Circuit

BLOWER
RELAY

ETACS-
ECU 

HEATER 
CONTROL UNIT

BLOWER
MOTOR

POWER
TRANSISTOR

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

ACB02708

FUSIBLE
LINK

42

AC612706

Connector: C-110 <LHD>

AL

AC612709

Connectors: C-303, C-309, C-315 <LHD>

AS

C-309 (B)

C-303

C-315

ETACS-ECU

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-47

COMMENTS ON TROUBLE SYMPTOM
If the blower motor is not energised, the blower relay 
system is suspected.

PROBABLE CAUSES

• Malfunction of the blower relay

• Damaged wiring harness or connector

• Malfunction of the ETACS-ECU

DIAGNOSTIC PROCEDURE

STEP 1. Connector check: C-303 blower relay 
connector

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair the connector concerned.

STEP 2. Measure the voltage at C-303 blower 
relay connector.
(1) Remove the relay, and measure at the junction 

block side.

(2) Voltage between terminals 1, 4 and body earth

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Go to Step 3.

STEP 3. Check the wiring harness between C-303 
blower relay connector terminal No. 1, 4 and 
fusible link (42) .

• Check the power supply line for open circuit.

NOTE: Prior to the wiring harness inspection, check 
ETACS-ECU connector C-309, and repair if neces-
sary.

Q: Is the check result normal?

YES : 

Intermittent malfunction (Refer to GROUP 

00 

− How to Use Troubleshooting/

Inspection Service Points - How to Cope 
with Intermittent Malfunction ).

NO : 

Repair the wiring harness.

STEP 4. Connector check: C-110 blower motor 
connector

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Repair the connector concerned.

STEP 5. Check the wiring harness between C-110 
blower motor connector terminal No. 1 and C-303 
blower relay connector terminal No. 3.
NOTE: Prior to the wiring harness inspection, check 
junction block connector C-315, and repair if neces-
sary.

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Repair the wiring harness.

STEP 6. Retest the system.
 Check that the blower motor is energised.

Q: Is the check result normal?

YES : 

Intermittent malfunction (Refer to GROUP 

00 

− How to Use Troubleshooting/

Inspection Service Points - How to Cope 
with Intermittent Malfunction ).

NO : 

Replace the ETACS-ECU.

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-48

INSPECTION PROCEDURE 8: Heater control unit power supply system

Heater Control Unit Power Source Circuit

IGNITION 
SWITCH (IG1)

ETACS-
ECU

HEATER CONTROL 
UNIT

IG1 
RELAY

FUSIBLE 
LINK

38

FUSIBLE 
LINK

44

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

POWER 
SOURCE

POWER 
SOURCE

ENGINE 
COMPARTMENT

RELAY BOX

 

 

 

 

 

 

 

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