Mitsubishi Montero (2002-2004). Manual - part 92

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-61

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TECHNICAL DESCRIPTION (COMMENT)
If the blower fan and motor does not turn when the 
blower switch is operated, the blower motor circuit 
may be defective.

.

TROUBLESHOOTING HINTS

• Malfunction of the blower relay

• Malfunction of the heater blower controller unit

• Malfunction of the flexible flat cable

• Malfunction of the blower motor

• Malfunction of the automatic air-conditioning con-

trol panel

• Damaged harness wires or connectors

DIAGNOSIS

STEP 1. Using scan tool MB991502, check actuator test 
item 01, item 02, item 03 and item 04: Blower motor.
Carry out the actuator test.
Item 01, 02, 03 and 04: Blower motor
Q: Do the check results show "Stop" (01 activated), "low 

speed" (02 activated), "medium speed" (03 activated), 
and "high speed" (04 activated)?
YES :  Go to Step 25.
NO :   Go to Step 2.

AC204171 BC

D-17 D-113

CONNECTORS : D-17, D-113

AC204170

CONNECTORS : D-23, D-28

DW

D-28

D-23(B)

AC204173

CONNECTORS : D-208, D-209, D-211, D-218

BH

D-208

D-218

D-209

D-211(B)

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-62

STEP 2. Measure the voltage at blower motor connector D-
113.
(1) Disconnect blower motor connector D-113, and measure 

the voltage at the harness side.

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

(4) Measure the voltage between terminal 1 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 14.
NO :   Go to Step 3.

STEP 3. Check the front blower relay continuity.
Follow the table below to check the front blower relay for conti-
nuity.

Q: Is the front blower relay continuity in good condition?

YES : Go to Step 4.
NO :  Replace the front blower relay. The blower motor 

should operate normally.

AC204171

CONNECTOR : D-113

AR

HARNESS 
SIDE

1

2

AC204738 DB

HARNESS SIDE : D-113

1

2

BATTERY VOLTAGE

TESTER 
CONNECTION 

SPECIFIED 
CONDITION

Not applied

2 

− 5

Open circuit

• Connect terminal 3 

to the positive 
battery terminal

• Connect terminal 1 

to the negative 
battery terminal

2 

− 5

Less than 2 ohms

AC204714AB

FRONT BLOWER RELAY

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-63

STEP 4. Measure the voltage at front blower relay 
connector D-218.
(1) Disconnect front blower relay connector D-218, and 

measure the voltage at the junction block side.

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

(3) Measure the voltage between terminal 3 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 7.
NO :   Go to Step 5.

STEP 5. Check front blower relay connector D-218 for 
damage.
Q: Is front blower relay connector D-218 in good 

condition?
YES : Go to Step 6.
NO :  Repair or replace the connector. Refer to GROUP 

00E, Harness Connector Inspection 

P.00E-2

. The 

blower motor should operate normally.

AC204173

CONNECTOR : D-218

BE

JUNCTION BLOCK
SIDE

1

2

5

4

3

AC204738 DG

JUNCTION BLOCK SIDE : D-218

1

2

5

4

3

AC204173

CONNECTOR : D-218

BE

JUNCTION BLOCK
SIDE

1

2

5

4

3

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-64

STEP 6. Check the wiring harness between front blower 
relay connector D-218 (terminal 3) and the ignition switch 
(IG2).
NOTE: Also check junction block connector D-208. If junction 
block connector D-208 is damaged, repair or replace the con-
nector as described in GROUP 00E, Harness Connector 
Inspection 

P.00E-2

.

Q: Is the wiring harness between front blower relay 

connector C-218 (terminal 3) and the ignition switch 
(IG2) in good condition?
YES : The front blower motor should operate normally.
NO :  Repair the wiring harness. The blower motor should 

operate normally.

STEP 7. Measure the voltage at front blower relay 
connector D-218.
(1) Disconnect front blower relay connector D-218, and 

measure the voltage at the junction block side.

(2) Measure the voltage between terminal 2 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 10.
NO :   Go to Step 8.

AC204191

JUNCTION BLOCK
(FRONT VIEW)

AC204191

CONNECTORS : D-208, D-218

D-208

HARNESS SIDE

D-218

RELAY SIDE

AT

D-208

D-218

1

2

3

5

6

4

1

2

5

4

3

AC204173

CONNECTOR : D-218

BE

JUNCTION BLOCK
SIDE

1

2

5

4

3

AC204738 DF

JUNCTION BLOCK SIDE : D-218

1

2

5

4

3