1999 MITSUBISHI LANCER EVOLUTION VI ignition

FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-45
Inspection procedure 7
Blower does not operate.
Probable cause
If no air comes out of the blower even though the blower switch is on, the
cause is probably a malfunction of the blower motor relay circuit.
Malfunction of blower motor relay

Malfunction of blower motor

Malfunction of connector or harness

Malfunction of A/C-ECU
Can an operating sound be heard when the blower speed change-
over switch is operated?NOInspection procedure 15 (Refer to P.55-52.)
YES

Blower motor relay check (Refer to P.55-13.)

Blower motor check (Refer to P.55-21.)NG
Repair
OK
Measure at the blower motor relay connector B-72.

Disconnect the connector, and measure at the harness
side connector.
(1) Continuity between terminal (1) and body earth
OK:Continuity
(2) Voltage between terminal (3) and body earth (Ignition
switch: ON)
OK:System voltage
(3) Voltage between terminal (5) and body earth
OK:System voltage(1) NGCheck the harness between the blower motor relay and the body
earth, and repair if necessary.
(2) NG
Check the harness between the blower motor relay and the ignition
switch, and repair if necessary.
(3) NG
Check the harness between the blower motor relay and the fusible
link No.1, and repair if necessary.
OK
Measure at the blower motor connector B-33.

Disconnect the connector, and measure at the harness
side connector.

Voltage between terminal (1) and body earth (Ignition
switch: ON)
OK:System voltageNGCheck the following connector:
B-76
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the blower motor relay and the blower
motor, and repair if necessary.
OK
Check the following connector:
B-33NG
Repair
OK
Check the trouble symptom.NGCheck the harness between the blower motor and earth, and
repair if necessary.

FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-46
Inspection procedure 8
Blower does not operate in HI mode.
Probable cause
If the blower does not operate in HI mode when the temperature is set to 17 or
32, the cause is probably a malfunction of the blower motor HI relay circuit system.
Malfunction of blower motor HI relay

Malfunction of blower motor

Malfunction of connector or harness

Malfunction of A/C-ECU
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the blower motor HI relay and the
A/C-ECU, and repair if necessary.
NG
Repair
OK
Check the trouble symptom.
NG
Check the harness between the blower motor HI relay and the
blower motor, and repair if necessary.
OK
Measure at the blower motor HI relay connector B-34.

Disconnect the connector, and measure at the harness
side connector.
(1) Connect terminal (1) to earth.
OK:Blower operates.
(2) Continuity between terminal (3) and body earth
OK:Continuity
(3) Voltage between terminal (4) and body earth (Ignition
switch: ON)
OK:System voltage(1) NGCheck the following connector:
B-34

Blower motor HI relay check (Refer to P.55-57.)

Blower motor check (Refer to P.55-21.)NG
Repair
NG
Repair
OK
Check the trouble symptom.
NG
Check the harness between the blower motor HI relay and the
body earth, and repair if necessary.
(2) NG
Check the following connector:
B-34
NG
Repair
OK
Check the trouble symptom.
NG
Check the harness between the blower motor HI relay and the
junction block, and repair if necessary.
(3) NG
Check the following connector:
B-34
NG
Repair OK
Check the trouble symptom.
YES
Check the following connector:
B-04
OK
Separate A/C-ECU connector B-04 and connect the terminal (12)
of the harness side connector to the earth. Does the blower
operate?NOCheck the following connector:
B-34
NG
Replace the A/C-ECU.

FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-47
Inspection procedure 9
Blower air amount cannot be changed.
Probable cause
If the blower does not operate in any mode other than HI setting, the cause is
probably a malfunction of the power transistor system.
Malfunction of power transistor

Malfunction of connector or harness

Malfunction of A/C-ECU
Measure at the power transistor connector B-37.

Blower switch position: LO

Connect the connector.
(1) Continuity between terminal (1) and body earth
OK:Continuity
(2) Voltage between terminal (2) and body earth (Ignition
switch: ON)
OK:System voltage – 2 V
(3) Voltage between terminal (4) and body earth (Ignition
switch: ON)
OK:Approx. 1.3 VOKCheck the following connector:
B-37
NG
Repair OK
Check the trouble symptom.
(1) NG
Check the harness between the power transistor and the body
earth, and repair if necessary.
(2) NG
Check the harness between the power transistor and the blower
motor, and repair if necessary.
(3) NG
Measure at the A/C-ECU connector B-04.

Blower switch position: LO

Connect the connector.
(1) Voltage between terminal (1) and body earth (Ignition
switch: ON)
OK:Approx. 7 V
(2) Voltage between terminal (2) and body earth (Ignition
switch: ON)
OK:Approx. 1.3 VNGCheck the following connector:
B-04
NG
Repair OK
Check the trouble symptom.
OK
Check the harness between the power transistor and the A/C-ECU.NG
Repair
OK
Replace the power transistor.
NG
Replace the power transistor.
NG
Replace the A/C-ECU.
Inspection procedure 10
Air outlet port cannot be changed.
Probable cause
The cause is probably a malfunction of the air outlet port changeover signal
input system or output system. The MUT-II can be used to check the
diagnosis codes in order to check the cause of the problem for each separate
system.
Malfunction of air outlet changeover damper
potentiometer

Malfunction of air outlet changeover damper
motor

Malfunction of air outlet changeover damper

Malfunction of connector or harness

Malfunction of A/C-ECU
Can an operating sound be heard when the air outlet port
changeover switch is operated?NOInspection procedure 15 (Refer to P.55-52.)
YES
MUT-II Self-Diag code
Is either code 32 or code 42 output?YESINSPECTION CHART FOR DIAGNOSIS CODES (Refer to
P.55-34.)
NO
Air outlet changeover damper checkNG
Repair
OK
Replace the A/C-ECU.

FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-51
NG
Repair OK
Check the trouble symptom.
NG
Repair
OK
Check the trouble symptom.
NG
Check the harness between the condenser fan motor relay (HI)
and the engine-ECU, and repair if necessary.
Measure at the radiator fan motor relay (HI) connector A-114X.

Disconnect the connector.
(1) Continuity between 4-B-59 and connector terminal (20)
OK:Continuity
(2) Voltage between terminal (2) and body earth (Ignition
switch: ON)
OK:System voltage
(3) Voltage between terminal (1) and body earth
OK:System voltage(1) NGCheck the following connectors:
A-114X, A-28, B-59
From the previous page
NG
Repair
OK
Check the trouble symptom.
NG
Check the harness between the condenser fan motor relay (HI)
and the ignition switch, and repair if necessary.
(2) NG
Check the following connector:
A-114X
NG
Repair
OK
Check the trouble symptom.
NG
Check the harness between the condenser fan motor relay (HI)
and the fusible link 2, and repair if necessary.
(3) NG
Check the following connector:
A-114X
OK
Measure at the condenser fan motor connector A-99.

Disconnect the connector, and measure at the harness
side connector.

Connect the terminal B-59 to the earth.

Voltage between terminal (1) and body earth (Ignition switch:
ON)
OK:System voltageNOCheck the following connector:
A-112X
NG
Check the harness between the condenser fan motor relay (HI)
and the condenser fan motor, and repair if necessary.
Inspection procedure 14
Rear defogger does not operate.
Probable cause
If the rear defogger does not operate when the rear defogger switch is turned
on (timer operates for 20 minutes), the cause is probably a malfunction of the
A/C-ECU power supply system (earth).
Malfunction of connector or harness

Malfunction of A/C-ECU
Can an operating sound be heard when the rear defogger switch
is operated?NOInspection procedure 15 (Refer to P.55-52.)
YES
Replace the A/C-ECU.

FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-52
Inspection procedure 15
A/C-ECU power supply circuit check
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the A/C-ECU and the fusible link
No.1, and repair if necessary.
OK
Check the trouble symptom.
NG
Check the harness between the A/C-ECU and the junction block,
and repair if necessary.
OK
Check the following connector:
B-05NG
Repair
OK
Check the trouble symptom.NGReplace the A/C-ECU.
NG
Repair
OK
Check the trouble symptom.
NG
Check the harness between the A/C-ECU and the body earth,
and repair if necessary.
NG
Repair
OK
Measure at the A/C-ECU connector B-05.

Disconnect the connector, and measure at the harness
side connector.

Continuity between terminal (29) and body earth
OK:Continuity

Continuity between terminal (35) and body earth
OK:ContinuityNGCheck the following connectors:
B-05, B-48, B-19, B-69, B-80
OK
Measure at the A/C-ECU connector B-05.

Disconnect the connector, and measure at the harness
side connector.

Voltage between terminal (28) and body earth (Ignition
switch: ON)
OK:System voltageNGCheck the following connectors:
B-49, B-75, B-76
Measure at the A/C-ECU connector B-04.

Disconnect the connector, and measure at the harness
side connector.

Voltage between terminal (3) and body earth
OK:System voltageNGCheck the following connectors:
B-49, B-75, B-73

FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-53
Inspection procedure 16
A/C compressor control circuit check
Measure at the A/C-ECU connector B-05.

Blower switch and A/C switch: ON

Setting temperature: 17C

Connect the connector.

Voltage between terminal (34) and body earth (Ignition
switch: ON)
OK:System voltageNGCheck the following connector:
B-05
NG
Repair OK
Check the trouble symptom.
NG
Replace the A/C-ECU.
OK
Measure at the A/C compressor relay connector A-116X.

Disconnect the connector, and measure at the harness
side connector.

Voltage between terminal (2) and body earth
OK:System voltageNGCheck the following connectors:
A-49, B-15, B-05
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the A/C-ECU and the A/C compressor
relay, and repair if necessary.
OK
Measure at the engine-ECU connector B-54 or B-59.

Disconnect the connector, and measure at the harness
side connector.

Voltage between terminal (21) or (22) and body earth
OK:System voltageNGCheck the following connectors:
A-28, A-116X
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the A/C compressor relay and the
engine-ECU, and repair if necessary.
OK
Replace the engine-ECU.

FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-54
DATA LIST REFERENCE TABLE
Check itemCheck conditionNormal condition
Inside air temperature sensor

MUT-II (11)Ignition switch: ONInside air temperature and temper-
ature displayed on the MUT-II are
identical.
Outside air temperature sen-
sor

MUT-II (13)Ignition switch: ONOutside air temperature and tem-
perature displayed on the MUT-II
are identical.
Heater water temperature
sensor

MUT-II (15)Ignition switch: ONHeater core surface temperature
and temperature displayed on the
MUT-II are identical.
Air thermo sensor

MUT-II (21)Ignition switch: ONEvaporator surface temperature
and temperature displayed on the
MUT-II are identical.
Photo sensor

MUT-II (25)Ignition switch: ONAmount of incident light is propor-
tional to voltage displayed on the
MUT-II.
Air mix damper potentiometer

MUTII(31)
Ignition switch: ONDamper positionOpening degree (%)

MUT-II (31)MAX. HOTApprox. 100
MAX. COOLApprox. 0
Air outlet changeover damper
potentiometer
Ignition switch: ONDamper positionOpening degree (%)
potentiometer

MUT-II (32)FACEApprox. 0
FOOTApprox. 50
FOOT/DEF.Approx. 75
DEF.Approx. 100
CHECK AT THE A/C-ECU TERMINALS
A/C-ECU
The parenthesized values in “Normal condition” column are for your reference.
Terminal
No.
Check itemCheck conditionNormal condition
1Front power transistor collector outputWhen blower switch is at OFFSystem voltage
When blower switch is at LOApprox. 7 V
When blower switch is at HIAlmost no voltage (0 V)
2Front power transistor base outputWhen blower switch is at OFF0 V
When blower switch is at LOApprox. 1.3 V
When blower switch is at HIApprox. 2.5 V
3BackupAt all timesSystem voltage

FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-55
Terminal
No.Normal condition Check condition Check item
4Heater water temperature sensor
inputWhen sensor section temperature is
25C (4 kΩ)2.3 – 2.9 V
5Air mix damper potentiometer inputWhen damper is moved to MAX. HOT
position4.7 – 5.0 V
6Air outlet changeover damper poten-
tiometer inputWhen damper is moved to DEF.
position4.8 – 5.2 V
7Outside air temperature sensor inputWhen sensor section temperature is
25C (4 kΩ)2.3 – 2.9 V
8Air thermo sensor inputWhen sensor section temperature is
25C (4 kΩ)2.3 – 2.9 V
9Photo sensor (–)At luminous intensity of 0 lux0 V
At luminous intensity of 100,000 lux or
more–0.1 – 0.2 V
10Sensor power supplyAt all times4.8 – 5.2 V
12Blower motor HI relay (Exciting circuit)When blower switch is in HI1.5 V or less
When blower switch is in a position
other than HISystem voltage
16Rear defoggerWhen rear defogger switch is ON1.5 V or less
When rear defogger switch is OFFSystem voltage
17Diagnosis date outputWhen ignition switch is ON0 V ↔ 12 V
18Diagnosis control outputWhen ignition switch is ONSystem voltage – 2 V
19Photo sensor (+)At all times0 V
20Sensor earthAt all times0 V
21Air outlet changeover damper motor
(FACE)When damper is moved to FACE
position10 V
When damper is moved to DEF.
positionAlmost no voltage
(0.5 V)
22Air mix damper motor (MAX. COOL)When damper is moved to MAX.
COOL position10 V
When damper is moved to MAX. HOT
positionAlmost no voltage
(0.5 V)
23Inside/outside air changeover damper
motor (Inside)When switch is set to inside air
positionAlmost no voltage
(0.5 V)
When switch is set to outside air
position10 V
24Air outlet changeover damper motor
(DEF.)When damper is moved to FACE
positionAlmost no voltage
(0.5 V)
When damper is moved to DEF.
position10 V