2005 MITSUBISHI 380 heater

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-95
STEP 8. Check the wiring harness between blower relay
connector C-202 (terminal 5) and fusible link (1).

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 VENTILATION55-99
STEP 15. Check the wiring harness between power
transistor connector C-104 (terminal 4) and blower motor
connector C-115 (terminal 2).
Q: Is the wiring harness between power transistor
connector C-104 (terminal 4) and blower motor
connector C-115 (terminal 2) in good condition?
YES : Go to Step 16.
NO : Repair the wiring harness. The blower motor should
operate normally.
STEP 16. 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 17.
NO : Repair the wiring harness. The blower motor should
operate normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-100
STEP 17. Replace the power transistor.
Q: Does the blower motor operate normally?
YES : No action is necessary and testing is complete.
NO : Replace the A/C-ECU. Check that the air conditioning
works normally.
INSPECTION PROCEDURE 6: Front Blower Air Amount cannot be Changed.
.
CIRCUIT OPERATION
If the blower motor speed cannot be changed, the
power transistor circuit is suspected.
.
TROUBLESHOOTING HINTS
Malfunction of the power transistor
Malfunction of the front 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 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 2.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2.The
blower motor should operate normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-101
STEP 2. 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 4.
NO : Go to Step 3.
STEP 3. 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 : The blower motor should operate normally.
NO : Repair the wiring harness. The blower motor should
operate normally.
STEP 4. Check blower motor connector C-115 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is blower motor connector C-115 in good condition?
YES : Go to Step 5.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2.The
blower motor should operate normally.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-102
STEP 5. Check the wiring harness between power
transistor connector C-104 (terminal 4) and blower motor
connector C-115 (terminal 2).
Q: Is the wiring harness between power transistor
connector C-104 (terminal 4) and blower motor
connector C-115 (terminal 2) in good condition?
YES : Go to Step 6.
NO : Repair the wiring harness. The blower motor should
operate normally.
STEP 6. 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 7.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2.The
blower motor should operate normally.