INSPECTION PROCEDURE 10: Rear Window Defogger Function does not Operate.: Diagnosis

Required Special Tools: 

• MB991223: Harness Set
• MB992006: Extra Fine Probe

1. STEP 1. Check the A/C and outside/inside air selection damper control motor operation. 

   Q: Do the A/C and outside/inside air selection damper control motor work normally? 

   YES :  Go to Step 2.

   NO :  Refer to INSPECTION PROCEDURE 1, MALFUNCTION OF THE A/C-ECU POWER SUPPLY SYSTEM .

2. STEP 2. Check rear window defogger relay connector C-205 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is rear window defogger relay connector C-205 in good condition? 

   YES :  Go to Step 3.

   NO :  Repair or replace the connector. Refer to HARNESS CONNECTOR INSPECTION .

   Fig 1: Checking Condition Of Rear Window Defogger Relay Connector C-205

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. STEP 3. Check the rear window defogger relay continuity. 

   Follow the table below to check the rear window defogger relay for continuity.

   CONTINUITY CONDITIONS
   
   

   BATTERY VOLTAGE	CONNECT TESTER BETWEEN	SPECIFIED CONDITION
   Not applied	4 - 5	Open Circuit
   Connect terminal 1 to the positive battery terminal Connect terminal 3 to the negative battery terminal	4 - 5	Less than 2 ohms

   Q: Is the rear window defogger relay in good condition? 

   YES :  Go to Step 4.

   NO :  Replace the rear window defogger relay.

   Fig 2: Checking Condition Of Rear Window Defogger Relay Continuity

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4. STEP 4. Check A/C-ECU connector C-15 and rear window defogger connector F-01 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is A/C-ECU connector C-15 and rear window defogger connector F-01 in good condition? 

   YES :  Go to Step 5.

   NO :  Repair or replace the connector. Refer to HARNESS CONNECTOR INSPECTION .

   Fig 3: Identifying Connector C-15 Terminals

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   Fig 4: Checking Condition Of Rear Window Defogger Connector F-01

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5. STEP 5. Measure the voltage at rear window defogger connector F-01. 
   1. Disconnect rear window defogger connector F-01, and measure the voltage at the harness side.
      Fig 5: Locating Rear Window Defogger Connector F-01

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   2. Disconnect A/C-ECU connector C-15 and ground harness side terminal No.8.
   3. Turn the ignition switch to the "ON" position.
      Fig 6: Identifying Connector C-15 Terminals

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      Fig 7: Grounding C-15 Harness Side Terminal No. 8

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   4. Measure the voltage between rear window defogger connector F-01 terminal No.1 and ground.
      • The measured value should be approximately 12 volts (battery positive voltage).

   Q: Is the measured voltage approximately 12 volts? 

   YES :  Go to  Step 12.

   NO :  Go to Step 6.

   Fig 8: Measuring Voltage Between Rear Window Defogger Connector F-01 Terminal No. 1 & Ground

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
6. STEP 6. Measure the voltage at rear window defogger relay connector C-205. 
   1. Disconnect rear window defogger relay connector C-205, and measure the voltage at the junction block side.
      Fig 9: Identifying Rear Window Defogger Relay Connector C-205

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   2. Measure the voltage between terminal 5 and ground.
      • The measured value should be approximately 12 volts (battery positive voltage).

   Q: Is the measured voltage approximately 12 volts? 

   YES :  Go to  Step 8.

   NO :  Go to Step 7.

   Fig 10: Measuring Voltage Between Terminal 5 & Ground

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
7. STEP 7. Check the wiring harness between rear window defogger relay connector C-205 (terminal 5) and the fusible link (1). 
   Fig 11: Identifying Connector C-204 & C-205

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   NOTE: Also check intermediate connector C-24 and junction block connector C-204 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-24 and junction block connector C-204 is damaged, repair or replace the connector as described in HARNESS CONNECTOR INSPECTION .

   Q: Is the wiring harness between rear window defogger relay connector C-205 (terminal 5) and the fusible link (1) in good condition? 

   YES :  It can be assumed that this malfunction is intermittent. Refer to - How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .

   NO :  Repair or replace the wiring harness. Refer to HARNESS CONNECTOR INSPECTION .

   Fig 12: Identifying Connector A-24 Terminals

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
8. STEP 8. Measure the voltage at rear window defogger relay connector C-205. 
   1. Disconnect rear window defogger relay connector C-205, and measure the voltage at the junction block side.
   2. Turn the ignition switch to the "ON" position.
      Fig 13: Identifying Rear Window Defogger Relay Connector C-205

      Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   3. Measure the voltage between terminal 1 and ground.
      • The measured value should be approximately 12 volts (battery positive voltage).

   Q: Is the measured voltage approximately 12 volts? 

   YES :  Go to  Step 10.

   NO :  Go to Step 9.

   Fig 14: Measuring Voltage Between Terminal 1 & Ground

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
9. STEP 9. Check the wiring harness between rear window defogger relay connector C-205 (terminal 1) and ignition switch (IG2). 
   Fig 15: Identifying Connector C-202 & C-205

   Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   NOTE: Also check junction block connector C-202 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If junction block connector C-202 is damaged, repair or replace the connector as described in HARNESS CONNECTOR INSPECTION .

   Q: Is the wiring harness between rear window defogger relay connector C-205 (terminal 1) and ignition switch (IG2) in good condition? 

   YES :  It can be assumed that this malfunction is intermittent. Refer to - How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .

   NO :  Repair or replace the wiring harness. Refer to HARNESS CONNECTOR INSPECTION .

10. STEP 10. Check the wiring harness between rear window defogger relay connector C-205 (terminal 3) and A/C-ECU connector C-15 (terminal 8). 
    Fig 16: Identifying Connector C-15 Terminals

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    Fig 17: Identifying Rear Window Defogger Relay Connector C-205 & C-215

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    NOTE: Also check junction block connector C-215 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If junction block connector C-215 is damaged, repair or replace the connector as described in HARNESS CONNECTOR INSPECTION .

    Q: Is the wiring harness between rear window defogger relay connector C-205 (terminal 3) and A/C-ECU connector C-15 (terminal 8) in good condition? 

    YES :  Go to Step 11.

    NO :  Repair or replace the wiring harness. Refer to HARNESS CONNECTOR INSPECTION .

11. STEP 11. Check the wiring harness between rear window defogger relay connector C-205 (terminal 4) and rear window defogger connector F-01 (terminal 1). 
    Fig 18: Identifying Connector C-205 & C-208

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    Fig 19: Locating Rear Window Defogger Connector F-01

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    NOTE: Also check junction block connector C-208 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If junction block connector C-208 is damaged, repair or replace the connector as described in HARNESS CONNECTOR INSPECTION .

    Q: Is the wiring harness between rear window defogger relay connector C-205 (terminal 4) and rear window defogger connector F-01 (terminal 1) in good condition? 

    YES :  It can be assumed that this malfunction is intermittent. Refer to - How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .

    NO :  Repair or replace the wiring harness. Refer to HARNESS CONNECTOR INSPECTION .

12. STEP 12. Check rear window defogger connector F-04 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

    Q: Is rear window defogger connector F-04 in good condition? 

    YES :  Go to Step 13.

    NO :  Repair or replace the connector. Refer to HARNESS CONNECTOR INSPECTION .

    Fig 20: Checking Condition Of Rear Window Defogger Connector F-04

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13. STEP 13. Measure the resistance at rear window defogger connector F-04. 
    1. Disconnect rear window defogger connector F-04, and measure the resistance at the wiring harness side.
       Fig 21: Identifying Rear Window Defogger Connector F-04

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    2. Measure the resistance value between terminal 1 and ground.

       OK: 1 kΩ or more 

    Q: Does the measured resistance value correspond with this range? 

    YES :  Go to  Step 15.

    NO :  Go to Step 14.

    Fig 22: Measuring Resistance Value Between Terminal 1 & Ground

    Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
14. STEP 14. Check the wiring harness between rear window defogger connector F-01 (terminal 1) and ground. 

    Q: Is the wiring harness between rear window rear window defogger connector F-01 (terminal 1) and ground in good condition? 

    YES :  It can be assumed that this malfunction is intermittent. Refer to - How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .

    NO :  Repair or replace the wiring harness. Refer to HARNESS CONNECTOR INSPECTION .

    Fig 23: Identifying Rear Window Rear Window Defogger Connector F-01

    Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
15. STEP 15. Check the rear window defogger. 
    1. Let the engine run at 2,000 r/min, and check the printed heater with the battery fully charged.
       Fig 24: Checking Condition Of Rear Window Defogger Printed Heater

       Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
    2. Turn on the rear window defogger switch, and use a voltmeter to measure the voltage in each printed heater at middle point A on the rear window glass.
       • The value should be approximately 6 volts.

    Q: Does the rear window defogger work normally? 

    YES :  Replace the A/C-ECU.

    NO :  Repair the rear window defogger.

    Fig 25: Normal & Abnormal Characteristics Curve (Voltage)

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