2005 MITSUBISHI 380 service

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-84
STEP 14. Check the wiring harness between powertrain
control module connector B-20 (terminal 6) and A/C
compressor clutch relay connector B-18X (terminal 3).
Q: Is the wiring harness between powertrain control
module connector B-20 (terminal 6) and A/C
compressor clutch relay connector B-18X (terminal 3) in
good condition?
YES : It can be assumed that this malfunction is intermittent.
Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
How to
Cope with Intermittent Malfunctions P.00-14.
NO : Repair the wiring harness. Check that the air
conditioning works normally.
STEP 15. Check A/C-ECU connector C-15 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is A/C-ECU connector C-15 in good condition?
YES : Go to Step 16.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2. Check
that the air conditioning works normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-86
STEP 17. Check the wiring harness between A/C
compressor clutch relay connector B-18X (terminal 4) and
A/C-ECU connector C-15 (terminal 10).
NOTE: Also check intermediate connectors A-13 and C-23 for
loose, corroded, or damaged terminals, or terminals pushed
back in the connector. If intermediate connector A-13 or C-23 is
damaged, repair or replace the connector as described in
GROUP 00E, Harness Connector Inspection P.00E-2.
Q: Is the wiring harness between A/C compressor clutch
relay connector B-18X (terminal 4) and A/C-ECU
connector C-15 (terminal 10) in good condition?
YES : It can be assumed that this malfunction is intermittent.
Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
How to
Cope with Intermittent Malfunctions P.00-14.
NO : Repair the wiring harness. Check that the air
conditioning works normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-88
STEP 21. Check the A/C pressure sensor operation.
(1) Assemble a gauge manifold on the high pressure service
valve.
(2) Disconnect the A/C pressure sensor connector and connect
special tool test harness MB991658 as shown in the
illustration.
(3) Turn ON the engine and then turn ON the air conditioner
switch.
(4) At this time, check to see that the voltage of A/C pressure
sensor terminal No. 2 reflects the specifications of the
figure.
NOTE: The allowance shall be defined as
5%.
Q: Is the A/C pressure sensor operating properly?
YES : Go to Step 22.
NO : Replace the A/C pressure sensor. Check that the air
conditioning works normally.
STEP 22. Check the refrigerant level.
Use the refrigerant recovery station to remove all of the refrig-
erant, and then calculate the amount of the refrigerant and
charge it.
Q: Is the refrigerant level correct?
YES : Go to Step 23.
NO : Correct the refrigerant level (Refer to On-vehicle
Service P.55-144). Check that the air conditioning
works normally.
STEP 23. Replace the A/C-ECU.
Q: Does the A/C operate normally?
YES : The procedure is complete.
NO : Replace the powertrain control module. Check that
the air conditioning works normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-93
STEP 6. Check the wiring harness between blower relay
connector C-202 (terminal 1) and the ignition switch (IG2).
NOTE: Also check junction block connector C-215 for loose,
corroded, or damaged terminals, or terminals pushed back in
the connector. If junction block connector C-215 is damaged,
repair or replace the connector as described in GROUP 00E,
Harness Connector Inspection P.00E-2.
Q: Is the wiring harness between blower relay connector
C-202 (terminal 1) and the ignition switch (IG2) in good
condition?
YES : It can be assumed that this malfunction is intermittent.
Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
How to
Cope with Intermittent Malfunctions P.00-14.
NO : Repair the wiring harness. The blower motor should
operate normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-96
NOTE: Also check intermediate connector C-31 and junction
block connector C-216 for loose, corroded, or damaged termi-
nals, or terminals pushed back in the connector. If intermediate
connector C-31, junction block connector C-216 is damaged,
repair or replace the connector as described in GROUP 00E,
Harness Connector Inspection P.00E-2.
Q: Is the wiring harness between blower relay connector
C-202 (terminal 5) and fusible link (1) in good condition?
YES : It can be assumed that this malfunction is intermittent.
Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
How to
Cope with Intermittent Malfunctions P.00-14.
NO : Repair the wiring harness. The blower motor should
operate normally.
STEP 9. Check the wiring harness between blower relay
connector C-202 (terminal 3) and A/C-ECU connector C-15
(terminal 9).

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-97
NOTE: Also check junction block connector C-211 for loose,
corroded, or damaged terminals, or terminals pushed back in
the connector. If junction block connector C-211 is damaged,
repair or replace the connector as described in GROUP 00E,
Harness Connector Inspection P.00E-2.
Q: Is the wiring harness between blower relay connector
C-202 (terminal 3) and A/C-ECU connector C-15
(terminal 9) in good condition?
YES : Go to Step 10.
NO : Repair the wiring harness. The blower motor should
operate normally.
STEP 10. Check the wiring harness between blower motor
connector C-115 (terminal 1) and blower relay connector
C-202 (terminal 4).
Q: Is the wiring harness between blower motor connector
C-115 (terminal 1) and blower relay connector C-202
(terminal 4) in good condition?
YES : It can be assumed that this malfunction is intermittent.
Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
How to
Cope with Intermittent Malfunctions P.00-14.
NO : Repair the wiring harness. The blower motor should
operate normally.
NOTE: Also check junction block connector C-215 for loose,
corroded, or damaged terminals, or terminals pushed back in
the connector. If junction block connector C-215 is damaged,
repair or replace the connector as described in GROUP 00E,
Harness Connector Inspection P.00E-2.
STEP 11. Check the blower fan and motor operation.
When battery voltage is applied between the terminals, check
that the motor operates. Also, check that there is no abnormal
noise.
Q: Is there any abnormal noise?
YES : Go to Step 12.
NO : Replace the blower relay. The blower motor should
operate normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-98
STEP 12. Check blower power transistor connector C-104
for loose, corroded or damaged terminals, or terminals
pushed back in the connector.
Q: Is power transistor connector C-104 in good condition?
YES : Go to Step 13.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2.The
blower motor should operate normally.
STEP 13. Measure the resistance at power transistor
connector C-104.
(1) Disconnect power transistor connector C-104, and measure
the resistance at the wiring harness side.
(2) Measure the resistance value between terminal 2 and
ground.
The measured value should be 2 ohms or less.
Q: Does the measured resistance value correspond with
this range?
YES : Go to Step 15.
NO : Go to Step 14.
STEP 14. Check the wiring harness between power
transistor connector C-104 (terminal 2) and ground.
Q: Is the wiring harness between power transistor
connector C-104 (terminal 2) and ground in good
condition?
YES : It can be assumed that this malfunction is intermittent.
Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
How to
Cope with Intermittent Malfunctions P.00-14.
NO : Repair the wiring harness. The blower motor should
operate normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-103
STEP 7. Check the wiring harness between power
transistor connector C-104 (terminals 1 and 3) and
A/C-ECU connector C-15 (terminals 17 and 18).
Q: Are the wiring harness between power transistor
connector C-104 (terminals 1 and 3) and A/C-ECU
connector C-15 (terminals 17 and 18) in good condition?
YES : Go to Step 8.
NO : Repair the wiring harness. The blower motor should
operate normally.
STEP 8. Replace the power transistor.
Q: Does the blower motor operate normally?
YES : It can be assumed that this malfunction is intermittent.
Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
How to
Cope with Intermittent Malfunctions P.00-14.
NO : Replace the A/C-ECU. Check that the air conditioning
works normally.