2005 MITSUBISHI LANCER Heater air conditioner and ventilation

TROUBLESHOOTING
HEATER, AIR CONDITIONER AND VENTILATION55-9
Prior to the wiring harness inspection, check
intermediate connector C-106, joint connector C-35,
junction block connectors C-209 and C-210, and
repair if necessary.
•Check the outside/inside air selection damper
control motor power supply line for open circuit.
Q: Is the check result normal?
YES :
The trouble can be an intermittent
malfunction (Refer to GROUP 00, How to
Cope with Intermittent Malfunction P.00-5).
NO : Repair the wiring harness.
STEP 5. Connector check: C-139 A/C-ECU
connector
Q: Is the check result normal?
YES :
Go to Step 6.
YES : Go to Step 7.
NO : Repair the connector.
AC303823
Connectors: C-209, C-210
AE
C-210
Junction block (front view)
C-209
C-209
Harness side
1016
145
12134117 238 9
C-210
Harness side
4 65321
AC303802
Connector: C-139

AE
C-139 (B)
Harness side
AC303818
Connector: C-139

AJ
Harness side
C-139 (B)
11 12657 8 9 103 421

TROUBLESHOOTING
HEATER, AIR CONDITIONER AND VENTILATION55-10
STEP 6. Check the wiring harness between C-107
outside/inside air selection damper control motor
connector (terminals 6 and 4) and C-139 A/C-ECU
connector (terminals 2 and 3).
NOTE: Prior to the wiring harness inspection, check
intermediate connector C-106, and repair if
necessary.
•Check the outside/inside air selection damper
control motor earth line for open or short circuit.
Q: Is the check result normal?
YES :
Go to Step 8.
NO : Repair the wiring harness.
STEP 7. Check the wiring harness between C-107
outside/inside air selection damper control motor
connector (terminals 6 and 4) and C-139 A/C-ECU
connector (terminals 10 and 11).
NOTE: Prior to the wiring harness inspection, check
intermediate connector C-106, and repair if
necessary.
•Check the outside/inside air selection damper
control motor earth line for open or short circuit.
Q: Is the check result normal?
YES :
Go to Step 8.
NO : Repair the wiring harness.
STEP 8. Check the outside/inside air selection
damper control motor
Refer to P.55-86.
Q: Does outside/inside air selection damper control
motor work normally?
YES :
Replace the manual air conditioner control
panel (A/C-ECU).
NO : Replace the outside/inside air selection
damper control motor.
AC303804AK
C-106
Harness side
C-107
Connectors: C-106, C-107

C-106C-107
AC303802
Connector: C-139

AE
C-139 (B)
Harness side
AC303816
Connectors: C-106, C-107
AO
C-107
C-106
Harness side
C-107C-106
AC303818
Connector: C-139

AJ
Harness side
C-139 (B)
11 12657 8 9 103 421

TROUBLESHOOTING
HEATER, AIR CONDITIONER AND VENTILATION55-11
INSPECTION PROCEDURE 3: When the A/C is Operating, Temperature Inside the Passenger
Compartment does not Decrease (Cool Air is not Emitted).
ENGINE-ECU
A/C-ECUDUAL
PRESSURE
SWITCH
RESISTOR ENGINE-A/T-ECU
HEATER CONTROL PANEL
Wire colour code
B : Black LG : Light green G : Green L : Blue W : White Y : Yellow SB : Sky blue
BR : Brown O : Orange GR : Gray R : Red P : Pink V : Violet
AIR THERMO
SENSOR
NOTEM/T
A/T
A/C-ECU System Circuit

TROUBLESHOOTING
HEATER, AIR CONDITIONER AND VENTILATION55-12
COMMENTS ON TROUBLE SYMPTOM
If cool air is not distributed when the A/C switch is on,
the air thermo sensor or the A/C compressor relay
system may be defective.
TROUBLESHOOTING HINTS
•Improper amount of refrigerant
•Malfunction of the air thermo sensor
•Malfunction of the dual pressure switch
•Malfunction of the A/C compressor relay
•Malfunction of the A/C refrigerant temperature
switch
•Malfunction of the magnetic clutch
•Malfunction of the manual air conditioner control
panel (A/C-ECU)
•Damaged the wiring harness or connectors
•Malfunction of the engine-ECU or the
engine-A/T-ECU
DIAGNOSIS
STEP 1. Check the defogger and outside/inside
air selection damper control motor operation.
Q: Do the 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.55-53 ."
STEP 2. Check the blower motor operation.
Q: Does the blower motor work normally?
YES :
Go to Step 3.
NO : Refer to Inspection procedure 5 "Blower fan
and motor do not turn P.55-29."
STEP 3. Check the A/C compressor.
Check the A/C compressor for compressor oil leaks.
Q: Is the check result satisfactory?
YES :
Go to Step 4.
NO : Replace the A/C compressor or the
expansion valve.
STEP 4. Connector check: B-114 A/C compressor
connector and C-123 engine-ECU connector
or C-122 engine-A/T-ECU connector
Q: Is the check result normal?
YES :
Go to Step 5.
NO : Repair the connector.
AC303782
Connector: B-114
<4G1-L.H.D.>
AC
Harness side
B-114 (B)
AC303790
Connector: B-114
<4G6-L.H.D.>
AC
Harness side
B-114 (B)
AC303805
Connectors: C-122 , C-123

C-122 (GR)
C-123 (Y)
C-122 Harness side
C-123
AE

TROUBLESHOOTING
HEATER, AIR CONDITIONER AND VENTILATION55-13
STEP 5. Voltage measurement at the B-114 A/C
compressor connector.
(1) Disconnect the connector, and measure at the
wiring harness side.
(2) Turn the ignition switch to the "ON" position.(3) Disconnect engine-ECU connector C-123, and
earth terminal 8.
(4) Disconnect engine-A/T-ECU connector C-122,
and earth terminal 20.
(5) Measure the voltage between terminal 1 and
body earth.
OK: System voltage
Q: Is the check result normal?
YES :
Go to Step 6.
NO : Refer to Inspection procedure 11 "A/C
compressor power supply system P.55-59."
AC303782
Connector: B-114
<4G1-L.H.D.>
AC
Harness side
B-114 (B)
AC303790
Connector: B-114
<4G6-L.H.D.>
AC
Harness side
B-114 (B)
AC303805
Connectors: C-122 , C-123

C-122 (GR)
C-123 (Y)
C-122 Harness side
C-123
AE
AC305159 Connector C-123
(Harness side)AB
AC305161
Connector C-122
(Harness side)
AB
AC301541EW
Connector B-114
(Harness side)
1

TROUBLESHOOTING
HEATER, AIR CONDITIONER AND VENTILATION55-14
STEP 6. Connector check: C-139 A/C-ECU
connector
Q: Is the check result normal?
YES :
Go to Step 7.
NO : Repair the connector.
STEP 7. Voltage measurement at C-139 A/C-ECU
connector.
(1) Disconnect the connector, and measure at the
wiring harness side.
(2) Turn the ignition switch to the "ON" position.
(3) Turn the blower switch to the "ON" position.
(4) Measure the voltage between terminal 8 and
body earth.
OK: System voltage
Q: Is the check result normal?
YES :
Go to Step 10.
NO : Go to Step 8.
STEP 8. Connector check: C-109 resistor
connector
Q: Is the check result normal?
YES :
Go to Step 9.
NO : Repair the connector.
STEP 9. Check the wiring harness between C-109
resistor connector terminal No.4 and C-139
A/C-ECU connector terminal No.8.
Q: Is the check result normal?
YES :
The trouble can be an intermittent
malfunction (Refer to GROUP 00, How to
Cope with Intermittent Malfunction P.00-5).
NO : Repair the wiring harness.
AC303802
Connector: C-139

AE
C-139 (B)
Harness side
AC303802
Connector: C-139

AE
C-139 (B)
Harness side
AC301541EX
Connector C-139
(Harness side)
9
1
1574
12
1110
23
13
5
14616
8
AC303804
Connector: C-109

AE
Harness side
AC303804
Connector: C-109

AE
Harness side
AC303802
Connector: C-139

AE
C-139 (B)
Harness side

TROUBLESHOOTING
HEATER, AIR CONDITIONER AND VENTILATION55-15
STEP 10. Connector check: A-31 dual pressure
switch connector
Q: Is the check result normal?
YES :
Go to Step 11.
NO : Repair the connector.
STEP 11. Check the dual pressure switch
operation.
Refer to P.55-69.
Q: Is the dual pressure switch operating properly?
YES :
Go to Step 12.
NO : Replace the dual pressure switch.
STEP 12. Connector check: C-106 air thermo
sensor connector
Q: Is the check result normal?
YES :
Go to Step 13.
NO : Repair the connector.
STEP 13. Check the wiring harness between
C-106 air thermo sensor connector (terminals 4
and 5) and C-139 A/C-ECU connector (terminals
16 and 13).
•Check the air thermo sensor output and earth line
for open or short circuit.
Q: Is the check result normal?
YES :
Go to Step 14.
NO : Repair the wiring harness.
AC303839
Connector: A-31

AH
Harness side
A-31 (BR)
AC303804
Connector: C-106

AC
C-106
AC303804
Connector: C-106

AC
C-106
AC303802
Connector: C-139

AE
C-139 (B)
Harness side

TROUBLESHOOTING
HEATER, AIR CONDITIONER AND VENTILATION55-16
STEP 14. Check the wiring harness between A-31
dual pressure switch connector terminal No.1
and C-139 A/C-ECU connector terminal No.4.
NOTE:
Prior to the wiring harness inspection, check
intermediate connector C-114, and repair if
necessary.
•Check the dual pressure switch output line for
open or short circuit.
Q: Is the check result normal?
YES :
Go to Step 15.
NO : Repair the wiring harness.
STEP 15. Connector check: C-125 engine-ECU
connector or C-126 engine-A/T-ECU
connector
Q: Is the check result normal?
YES :
Go to Step 16.
NO : Repair the connector.
AC303839
Connector: A-31

AH
Harness side
A-31 (BR)
AC303802
Connector: C-139

AE
C-139 (B)
Harness side
AC303804
Connector: C-114

AN183
161514121745 8
20196721 2291025
1324 2312 11
AC303805
Connectors: C-125 , C-126
AG

C-126 (GR)
C-125Harness side
C-125 (Y)
C-126
38
46
45 44 43 42 41 40 3937 36 35 34 33 32 3177 76 75 74 73 72 71
78 79 80 81 82 83 84 85 86 87 88 89
90 98 97 96 95 94 93 92 91