2005 MITSUBISHI 380 Workshop Manual

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-116
STEP 8. Measure the voltage at defogger relay connector
C-201.
(1) Disconnect defogger relay connector C-201, and measure
the voltage at the junction block side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 1 and ground.
The measured value should be approximately 12 volts
(battery positive voltage).
Q: Is the measured voltage approx. 12 volts?
YES : Go to Step 10.
NO : Go to Step 9.
STEP 9. Check the wiring harness between defogger relay
connector C-201 (terminal 1) and ignition switch (IG2).

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-117
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 defogger relay connector
C-201 (terminal 1) and 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. Check that the defogger
system works normally.
STEP 10. 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 11.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2. Check
that the defogger system works normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-118
STEP 11. Check the wiring harness between defogger relay
connector C-201 (terminal 3) and A/C-ECU connector C-15
(terminal 8).
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 defogger relay connector
C-201 (terminal 3) and A/C-ECU connector C-15
(terminal 8) in good condition?
YES : Go to Step 12.
NO : Repair or replace the wiring harness. Refer to
GROUP 00E, Harness Connector Inspection
P.00E-2. Check that the defogger system works
normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-119
STEP 12. Check the wiring harness between defogger
relay connector C-201 (terminal 4) and choke coil
connector D-11 (terminal 1).
NOTE: Also check junction block connector C-204 for loose,
corroded, or damaged terminals, or terminals pushed back in
the connector. If junction block connector C-204 is damaged,
repair or replace the connector as described in GROUP 00E,
Harness Connector Inspection P.00E-2.
Q: Is the wiring harness between defogger relay connector
C-201 (terminal 4) and choke coil connector D-11
(terminal 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 or replace the wiring harness. Refer to
GROUP 00E, Harness Connector Inspection
P.00E-2. Check that the defogger system works
normally.
STEP 13. Check choke coil connector D-11 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is choke coil connector D-11 in good condition?
YES : Go to Step 14.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2. Check
that the defogger system works normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-120
STEP 14. Check the wiring harness between choke coil
connector D-11 (terminal 1) and rear glass solder joint.
Q: Is the wiring harness between choke coil connector
D-11 (terminal 1) and rear glass solder joint in good
condition?
YES : Go to Step 15.
NO : Repair or replace the wiring harness. Refer to
GROUP 00E, Harness Connector Inspection
P.00E-2. Check that the defogger system works
normally.
STEP 15. Check rear glass solder joints for loose,
corroded or damaged joints.
Q: Are solder joints in good condition?
YES : Go to Step 16.
NO : Repair solder joint. Check that the defogger system
works normally.
STEP 16. Check the wiring harness between RH rear glass
solder joint and earth point.
Q: Is the wiring harness between RH rear glass solder joint
and earth point in good condition?
YES : Go to Step 17.
NO : Repair or replace the wiring harness or repair solder
joint. . Check that the defogger system works
normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-121
STEP 17. Check the defogger.
(1) Let the engine run at 2,000 r/min, and check the printed
heater with the battery fully charged.
(2) Turn on the defogger switch, and use a voltmeter to
measure the voltage in each printed heater at middle point
A on the rear window glass.
The value should be approximately 6 volts.
Q: Does the defogger work normally?
YES : Replace the A/C-ECU. Check that the defogger
system works normally.
NO : Repair the defogger. Or replace rear glass. Refer to
GROUP 42, Rear Window Glass.P.42-12
INSPECTION PROCEDURE 9: Defogger Timer Function does not Operate.
.
CIRCUIT OPERATION
Turn ON the defogger switch. If the defogger does
not shut off after about 16 minutes then the defogger
timer is malfunctioning.
.
TROUBLESHOOTING HINT
Malfunction of the A/C-ECU
Malfunction of the defogger timer
Refer to component locations GROUP-70
Refer to configuration diagrams GROUP-80
Refer to circuit diagrams GROUP-90
DIAGNOSIS
Replace the A/C-ECU.

AUTO A/C DIAGNOSIS
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INSPECTION PROCEDURE 10: Malfunction of the A/C-ECU Power Supply System.
.
TECHNICAL DESCRIPTION (COMMENT)
The A/C-ECU power system may be defective if the
air conditioner, defogger, and outside/inside air
selection damper motor all do not operate normally.
.
TROUBLESHOOTING HINTS
Malfunction of the A/C-ECU
Damaged harness wires or connectors
Refer to component locations GROUP-70
Refer to configuration diagrams GROUP-80
Refer to circuit diagrams GROUP-90
DIAGNOSIS
Required Special Tool:
MB991223: Test Harness Set
STEP 1. Check A/C-ECU connector C-16 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is A/C-ECU connector C-16 in good condition?
YES : Go to Step 2.
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 VENTILATION55-123
STEP 2. Measure the voltage at A/C-ECU connector C-16.
(1) Disconnect A/C-ECU connector C-16 and measure the
voltage at the harness side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 28 and ground.
The measured value should be approximately 12 volts
(battery positive voltage).
Q: Is the measured voltage approx. 12 volts?
YES : Go to Step 4.
NO : Go to Step 3.
STEP 3. Check the wiring harness between A/C-ECU
connector C-16 (terminal 28) and the ignition switch (IG2).