Mitsubishi Lancer Evolution IX. Manual — part 539

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-29

TROUBLE SYMPTOM CHART

M1554005000571

SYMPTOM PROCEDURES

Inspection Procedure 1: Communication with the M.U.T.-II/III is not Possible.

Symptom

Inspection
procedure number

Reference page

Communication with the M.U.T.-II/III is not possible.

1

P.55-29

When the A/C is operating, temperature inside the
passenger compartment does not decrease (cool air is
not emitted).

2

P.55-32

A/C outlet air temperature cannot be set.

3

P.55-41

The blower does not work.

4

P.55-42

The blower air volume cannot be changed.

5

P.55-54

When sunlight intensity changes, blower air
temperature does not change.

6

P.55-56

The outside/inside air changeover is impossible.

7

P.55-58

Rear window defogger function does not operate.

8

P.55-63

Malfunction of the A/C-ECU power supply system.

9

P.55-73

A/C compressor power supply system.

10

P.55-79

Condenser fan does not operate.

11

P.55-86

Diagnosis Connector 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

<LHD>
<RHD>

DIAGNOSIS
CONNECTOR

FRONT SIDE

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-30

COMMENTS ON TROUBLE SYMPTOM

If communication with all other systems is not possi-
ble, there is a high possibility that there is a malfunc-
tion of the diagnosis line. If only the A/C system can
not communicate with the M.U.T.-II/III, the diagnosis
line between the A/C-ECU and the diagnosis con-
nector may be defective.

PROBABLE CAUSES

• Damaged the wiring harness or connectors

• Malfunction of the automatic A/C control panel

(A/C-ECU)

DIAGNOSIS PROCEDURE

STEP 1. Check the communication with other
systems.

Q: Is the communication with the other systems

possible using the M.U.T.-II/III?
YES :

Go to Step 2.

NO :

Check the diagnosis line using the
M.U.T.-II/III, and repair if necessary.

STEP 2. Check operations of the A/C, rear
window defogger and outside/inside air selection
damper control motor.

Q: Does the A/C, rear window defogger or

outside/inside air selection damper control motor
operate?
YES :

Go to Step 3.

NO :

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

P.55-73

."

STEP 3. Connector check: C-36 A/C-ECU
connector and C-14 diagnosis connector

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Repair the connector.

AC504641AD

Connector: C-14, C-36 <LHD>

Harness side

C-36

C-14

C-36 (B)

C-14

AC504625AE

Connector: C-14 <RHD>

Harness side

C-14 (B)

AC504618AJ

Connector: C-36 <RHD>

Harness side

C-36 (B)

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-31

STEP 4. Check the wiring harness between C-36
A/C-ECU connector (terminal 17 and 18) and C-14
diagnosis connector (terminal 11 and 1).

NOTE:

Prior to the wiring harness inspection, check joint
connector C-23 <LH drive vehicles> or C-21 <RH
drive vehicles> , and repair if necessary.

• Check the communication lines for open or short

circuit.

Q: Is the check result normal?

YES :

Replace the automatic A/C control panel

(A/C-ECU).

NO :

Repair the wiring harness.

AC504641AD

Connector: C-14, C-36 <LHD>

Harness side

C-36

C-14

C-36 (B)

C-14

AC504625AE

Connector: C-14 <RHD>

Harness side

C-14 (B)

AC504618AJ

Connector: C-36 <RHD>

Harness side

C-36 (B)

AC504618AM

Connector: C-21 <RHD>

AC504622AG

Connector: C-23 <LHD>

C-23 (B)

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-32

Inspection Procedure 2: When the A/C is Operating, Temperature Inside the Passenger Compartment
does not Decrease (Cool Air is not Emitted).

A/C-ECU System 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

DUAL
PRESSURE
SWITCH

LOW-
PRESSURE
SIDE

HIGH-
PRESSURE
SIDE

BLOWER LINER
CONTROLLER

ENGINE-ECU

AIR THERMO
SENSOR