Mitsubishi Galant (2004+). Manual - part 765

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-199

NOTE: Also check intermediate connector A-13, joint connec-
tor C-01, junction block connectors C-214 and C-215 for loose, 
corroded, or damaged terminals, or terminals pushed back in 
the connector. If intermediate connector A-13, joint connector 
C-01, junction block connector C-214 or 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 A/C compressor clutch 

relay connector B-18X (terminal 2) 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 

P.00-6

.

NO :  Repair the wiring harness. Check that the air 

conditioning works normally.

AC305210

A-13 (GR)

AR

CONNECTOR: A-13

AC305231

CONNECTOR: C-01

BO

AC305416

CONNECTORS: C-214, C-215

JUNCTION BLOCK 
(FRONT VIEW)

C-215

HARNESS SIDE

C-214

C-214

HARNESS SIDE

C-215

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1

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14

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12

13

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11

7

2

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AL

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-200

STEP 11. Measure the voltage at A/C compressor clutch 
relay connector B-18X. 

CAUTION

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.

AC305977AJ

CONNECTOR: B-18X

RELAY BOX SIDE

FRONT OF 
VEHICLE

JUNCTION BLOCK 
TRIANGLE MARK

AC209365GU

CONNECTOR B-18X 
(RELAY BOX SIDE)

AC305977AJ

CONNECTOR: B-18X

RELAY BOX SIDE

FRONT OF 
VEHICLE

JUNCTION BLOCK 
TRIANGLE MARK

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-201

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 

P.00-6

.

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.

AC305210

A-13 (GR)

AR

CONNECTOR: A-13

AC305977AJ

CONNECTOR: B-18X

RELAY BOX SIDE

FRONT OF 
VEHICLE

JUNCTION BLOCK 
TRIANGLE MARK

AC305214

B-28 (B)

HARNESS SIDE

AD

CONNECTOR: B-28 <2.4L>

AC305218

B-28 (B)

HARNESS SIDE

AB

CONNECTOR: B-28 <3.8 L>

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-202

STEP 14. Check the wiring harness between powertrain 
control module connector B-21 (terminal 81) and A/C 
compressor clutch relay connector B-18X (terminal 3).

Q: Is the wiring harness between powertrain control 

module connector B-21 (terminal 81) 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 

P.00-6

.

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.

AC305977AJ

CONNECTOR: B-18X

RELAY BOX SIDE

FRONT OF 
VEHICLE

JUNCTION BLOCK 
TRIANGLE MARK

AC305216

B-21 (B)

AC

CONNECTOR: B-21 <2.4L>

HARNESS SIDE

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AC305229

B-21 (B)

AB

HARNESS SIDE

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53

54

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CONNECTOR: B-21 <3.8 L>

AC305233

CONNECTOR: C-15

BG

C-105 (B)

HARNESS SIDE