Mitsubishi Colt Ralliart. Manual - part 531

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-32

Inspection Procedure 8: The rear window defogger does not work

REAR
WINDOW
DEFOGGER
RELAY

REAR WINDOW
DEFOGGER

METER AND A/C-ECU

COMBINATION METER

DEFOGGER DRIVE
CIRCUIT

Wire colour code
B : Black     LG : Light green     G : Green     L : Blue     W : White     Y : Yellow     SB : Sky blue
BR : Brown     O : Orange     GR : Gray     R : Red     P : Pink     V : Violet

FUSIBLE
LINK

6

IGNITION
SWITCH (IG2)

Defogger Circuit

CIRCUIT OPERATION

If the rear window defogger does not operate when 
the rear window defogger switch is turned on, the 
rear window defogger relay system may be defec-
tive.

TROUBLESHOOTING HINTS

• Malfunction of the combination meter (meter and 

A/C-ECU)

• Malfunction of the rear window defogger relay

• Damaged the wiring harness or connectors

• Malfunction of the rear window defogger

DIAGNOSIS PROCEDURE

Step 1. Check the A/C operation.

Q: Do the A/C work normally?

YES : 

Go to Step 2.

NO : 

Refer to Inspection procedure 3 "Cool air 
does not come 

P.55A-11

."

Main

Index

Group

TOC

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-33

Step 2. Connector check: B-15 combination 
meter connector and E-13 rear window defogger 
connector

AC401055

AE

Connector: B-15

B-15 (B)

Harness side

AC401046

Connector: E-13

AF

Harness side

E-13 (B)

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair the connector.

Step 3. Voltage measurement at E-13 rear window 
defogger connector. 

AC401046

Connector: E-13

AF

Harness side

E-13 (B)

(1) Disconnect the connector, and measure at the 

wiring harness side.

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

AC401055

AE

Connector: B-15

B-15 (B)

Harness side

AC309471

AC309471

Connector B-15
(Harness side)

AN

(3) Disconnect combination meter connector B-15 

and earth terminal 13.

AC400965

Connector E-13 
(Harness side)

AK

(4) Measure the voltage between terminal 1 and 

body earth.

OK: System voltage

Q: Is the check result normal?

YES : 

 Go to Step 12.

NO : 

 Go to Step 4.

Main

Index

Group

TOC

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-34

Step 4. Connector check: B-125 rear window 
defogger relay connector 

AC313824AK

Junction block side

Junction block (Front view)

Connector: B-125

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Repair the connector.

Step 5. Check the rear window defogger relay 
continuity.
 Refer to 

P.54A-122

.

Q: Is the rear window defogger relay in good 

condition?
YES : 

Go to Step 6.

NO : 

Replace the rear window defogger relay.

Step 6. Voltage measurement at B-125 rear 
window defogger relay connector. 

AC313824AK

Junction block side

Junction block (Front view)

Connector: B-125

(1) Remove the relay, and measure at the junction 

block side.

AC310507 FM

Connector B-125 
(Junction block side)

(2) Measure the voltage between terminal 3 and 

body earth.

OK: System voltage

Q: Is the check result normal?

YES : 

 Go to Step 8.

NO : 

 Go to Step 7.

Main

Index

Group

TOC

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55A-35

Step 7. Check the wiring harness between B-125 
rear window defogger relay connector terminal 
No.3 and the fusible link (6).

AC313824AK

Junction block side

Junction block (Front view)

Connector: B-125

NOTE: Prior to the wiring harness inspection, check 
junction block connector B-108, and repair if neces-
sary.

• Check the rear window defogger relay power 

supply line for open or short circuit.

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00, How to 
Cope with Intermittent Malfunction 

P.00-13

).

NO : 

Repair the wiring harness.

Step 8. Voltage measurement at B-125 rear 
window defogger relay connector. 

AC313824AK

Junction block side

Junction block (Front view)

Connector: B-125

(1) Remove the relay, and measure at the junction 

block side.

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

AC310507 FM

Connector B-125 
(Junction block side)

(3) Voltage between terminal 1 and body earth.

OK: System voltage

Q: Is the check result normal?

YES : 

 Go to Step 10.

NO : 

 Go to Step 9.

Step 9. Check the wiring harness between B-125 
rear window defogger relay connector No.1 and 
ignition switch (IG2).

AC313824AK

Junction block side

Junction block (Front view)

Connector: B-125

AC313826

Harness side

AE

Connector: B-130

Junction block (Rear view)

NOTE: Prior to the wiring harness inspection, check 
junction block connector B-130, and repair if neces-
sary.

• Check the rear window defogger power supply 

line for open circuit.

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00, How to 
Cope with Intermittent Malfunction 

P.00-13

).

NO : 

Repair the wiring harness.

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