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