Mitsubishi Galant 9G. Manual — part 280

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-196

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-197

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.

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-198

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

− 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.

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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CONNECTOR: B-21 <3.8 L>

AC305233

CONNECTOR: C-15

BG

C-105 (B)

HARNESS SIDE

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-199

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-21 and

ground harness side terminal No.81.

(3) Turn the ignition switch to the "ON" position.

AC305233

CONNECTOR: C-15

BG

C-105 (B)

HARNESS SIDE

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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CONNECTOR: B-21 <3.8 L>

AC306468

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AC306468

CONNECTOR B-21
(HARNESS SIDE)

AD