Mitsubishi Galant (2004+). Manual - part 750

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-139

STEP 22. Check the A/C pressure sensor operation.

1. Assemble a gauge manifold on the high pressure service 

valve.

2. Disconnect the A/C pressure sensor connector and connect 

special tool test harness MB991658 as shown in the illustra-
tion.

3. Turn ON the engine and then turn ON the air conditioner 

switch.

4. At this time, check to see that the voltage of A/C pressure 

sensor terminal No. 2 reflects the specifications of the fig-
ure.
NOTE: The allowance shall be defined as 

±

5%.

Q: Is the A/C pressure sensor operating properly?

YES : Go to Step 23.
NO :  Replace the A/C pressure sensor. Check that the air 

conditioning works normally.

STEP 23. Check the refrigerant level.

Use the refrigerant recovery station to remove all of the refrig-
erant, and then calculate the amount of the refrigerant and 
charge it.
Q: Is the refrigerant level correct?

YES : Go to Step 24.
NO :  Correct the refrigerant level (Refer to On-vehicle 

Service 

P.55A-266

). Check that the air conditioning 

works normally. 

STEP 24. Replace the A/C-ECU.
Q: Does the A/C operate normally?

YES : No action is necessary and testing is complete.
NO :  Replace the powertrain control module. Check that 

the air conditioning works normally. 

AC305034

A/C PRESSURE SENSOR

AD

AC307368

A/C 
PRESSURE 
SENSOR 
SIDE

MB991658

AB

HARNESS SIDE

AC208297AB

REFRIGERANT PRESSURE (MPa)

OUTPUT VOLTAGE 

(V)

0

1

2

3

5

4

1

2

3

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-140

INSPECTION PROCEDURE 5: Blower Fan and Motor do not Turn.

IGNITION
SWITCH (IG2)

1

FUSIBLE 
LINK

BLOWER 
SWITCH

BLOWER 
MOTOR

BLOWER 
RELAY

JUNCTION
BLOCK

JOINT CONNECTOR (2)

Blower Motor Circuit

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-141

.

CIRCUIT OPERATION
If the blower motor does not operate, the blower 
relay system is suspected.

.

TROUBLESHOOTING HINTS

• Malfunction of the blower relay

• Malfunction of the resistor

• Malfunction of the blower motor

• Malfunction of the A/C-ECU

• Damaged harness wires or connectors

DIAGNOSIS

Required Special Tool:

• MB991223: Test Harness Set

STEP 1. 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 2.
NO :  Repair or replace the connector. Refer to GROUP 

00E, Harness Connector Inspection 

P.00E-2

.The 

blower motor should operate normally.

AC305231

C-29

C-03

CONNECTORS: C-03, C-29

BK

AC305233BP

CONNECTORS: C-14, C-115

C-14

C-115

AC305415BD

CONNECTORS: C-202, C-211, C-215, C-216

JUNCTION BLOCK 
(FRONT VIEW)

C-216 (B)

C-215

C-202

C-211

AC305233BN

CONNECTOR: C-115

HARNESS SIDE

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-142

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) Turn the ignition switch to the "ON" position.
(3) Turn the blower switch to the "4 (HI)" position.

(4) Measure the voltage between 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 15.
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.

AC305233BN

CONNECTOR: C-115

HARNESS SIDE

AC209365

CONNECTOR C-115 
(HARNESS SIDE)

GW

AC305415BC

CONNECTOR: C-202

JUNCTION BLOCK SIDE

JUNCTION BLOCK 
(FRONT VIEW)