2005 MITSUBISHI 380 relay

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-82
STEP 11. Measure the voltage at A/C compressor clutch
relay connector B-18X.
The top and bottom of the A/C compressor connector are
difficult to identify. Prior to inspection, confirm the triangle
mark on the relay box.
(1) Disconnect A/C compressor connector B-18X and measure
the voltage at the wiring harness side.
(2) 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 13.
NO : Go to Step 12.
STEP 12. Check the wiring harness between A/C
compressor clutch relay connector B-18X (terminal 1) and
the battery.

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-83
NOTE: Also check intermediate connector A-13 for loose, cor-
roded, or damaged terminals, or terminals pushed back in the
connector. If intermediate connector A-13 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 1) and the battery 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 13. Check the wiring harness between A/C
compressor clutch relay connector B-18X (terminal 4) and
A/C compressor assembly connector B-28 (terminal 1).
Q: Is the wiring harness between A/C compressor clutch
relay connector B-18X (terminal 4) and A/C compressor
connector B-28 (terminal 1) in good condition?
YES : Go to Step 14.
NO : Repair the wiring harness. Check that the air
conditioning works normally.

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 VENTILATION55-85
STEP 16. Measure the voltage at A/C-ECU connector C-15.
(1) Disconnect A/C-ECU connector C-15 and measure the
voltage at the relay box side.
(2) Disconnect powertrain control module connector B-20 and
ground harness side terminal No.6.
(3) Turn the ignition switch to the "ON" position.
(4) Measure the voltage between A/C-ECU connector C-15
terminal No.10 and ground.
The measured value should be approximately 12 volts
(battery positive voltage).
Q: Does the measured voltage correspond with this range?
YES : Go to Step 18.
NO : Go to Step 17.

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 VENTILATION55-89
INSPECTION PROCEDURE 5: Front Blower Fan and Motor do not Turn.
.
CIRCUIT OPERATION
If the blower motor does not operate, the blower
relay system is suspected.
.
TROUBLESHOOTING HINTS
Malfunction of the front blower relay
Malfunction of the power transistor
Malfunction of the front blower motor
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

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-91
STEP 2. Measure the voltage at blower motor connector
C-115.
(1) Disconnect blower motor connector C-115, and measure
the voltage at the wiring harness side.
(2) Disconnect A/C-ECU connector C-15 and ground harness
side terminal No.9.
(3) Turn the ignition switch to the "ON" position.
(4) Measure the voltage between C-115 (terminal 1) and
ground.
The measured value should be approx. 12 volts (battery
positive voltage).
Q: Is the measured voltage approx. 12 volts?
YES : Go to Step 11.
NO : Go to Step 3.
STEP 3. Check blower relay connector C-202 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is blower relay connector C-202 in good condition?
YES : Go to Step 4.
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 VENTILATION55-92
STEP 4. Check the blower relay continuity.
Follow the table below to check the blower relay for continuity.
Q: Is the blower relay continuity in good condition?
YES : Go to Step 5.
NO : Replace the blower relay. The blower motor should
operate normally.
STEP 5. Measure the voltage at blower relay connector
C-202.
(1) Disconnect blower relay connector C-202, 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 7.
NO : Go to Step 6. BATTERY
VOLTAGETESTER
CONNECTIONSPECIFIED
CONDITION
Not applied 4
5 Open circuit
Connect
terminal 1 to the
positive battery
terminal
Connect
terminal 3 to the
negative battery
terminal4
5 Less than 2 ohms