Inspection Procedure 9

INSPECTION PROCEDURE 9: Rear Window Defogger Function does not Operate.

Rear Window Defogger Circuit Part 1:

Rear Window Defogger Circuit Part 2:

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 defective.

TROUBLESHOOTING HINTS
- Malfunction of the A/C-ECU
- Malfunction of the rear window defogger relay
- Damaged harness wires or connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe

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 10 "Malfunction of the A/C-ECU Power Supply system."

STEP 2. Measure the voltage at rear window defogger connector F-04.




1. Disconnect rear window defogger connector F-04, and measure the voltage at the junction block side.
2. Turn the rear window defogger switch to the "ON" position.




3. 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 10.

NO: Go to Step 8.

STEP 3. Check the rear window defogger relay continuity. Refer to Rear Window Defogger Switch - Inspection in Windows and Glass/Heated Glass Element Switch.

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

YES: Go to Step 4.

NO: Replace the rear window defogger relay. The rear window defogger system should work normally.

STEP 4. Measure the voltage at rear window defogger relay connector C-206.




1. Disconnect rear window defogger relay connector C-206, and measure the voltage at the junction block side.




2. Measure the voltage between terminal 5 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 rear window defogger relay connector C-206 for damage.

Q: Is rear window defogger relay connector C-206 in good condition?

YES: Go to Step 6.

NO: Repair or replace the connector. The rear window defogger system should work normally.










STEP 6. Check the wiring harness between rear window defogger relay connector C-206 (terminal 5) and the fusible link (1).

NOTE: Also check junction block connector C-204 and intermediate connector C-116. If junction block connector C-204 and intermediate connector C-116 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-206 (terminal 5) and the battery 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 the wiring harness. Check that the rear window defogger system works normally.

STEP 7. Measure the voltage at rear window defogger relay connector C-206.




1. Disconnect rear window defogger relay connector C-206, and measure the voltage at the junction block side.
2. Turn the ignition switch to the "ON" position.




3. 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 10.

NO: Go to Step 8.




STEP 8. Check rear window defogger relay connector C-206 for damage.

Q: Is rear window defogger relay connector C-206 in good condition?

YES: Go to Step 9.

NO: Repair or replace the connector. Check that the rear window defogger system works normally.




STEP 9. Check the wiring harness between rear window defogger relay connector C-206 (terminal 1) and ignition switch (IG2).

NOTE: Also check junction block connector C-203. If junction block connector C-203 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-206 (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 the wiring harness. Check that the rear window defogger system works normally.







STEP 10. Check rear window defogger relay connector C-206 and A/C-ECU connector C-25 for damage.

Q: Are rear window defogger relay connector C-206 and A/C-ECU connector C-25 in good condition?

YES: Go to Step 11.

NO: Repair or replace the connector. Check that the rear window defogger system works normally.







STEP 11. Check the wiring harness between rear window defogger relay connector C-206 (terminal 3) and A/C-ECU connector C-25 (terminal 16).

NOTE: Also check junction block connector C-205. If junction block connector C-205 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-206 (terminal 3) and A/C-ECU connector C-25 (terminal 16) in good condition?

YES: Go to Step 12.

NO: Repair or replace the wiring harness. Check that the rear window defogger system works normally.







STEP 12. Check rear window defogger relay connector C-206 and rear window defogger connector F-04 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are rear window defogger relay connector C-206 and rear window defogger connector F-04 in good condition?

YES: Go to Step 13.

NO: Repair or replace the connector. Check that the rear window defogger system works normally.







STEP 13. Check the wiring harness between rear window defogger relay connector C-206 (terminal 4) and rear window defogger connector F-04 (terminal 1).

NOTE: Also check junction block connector C-209. If junction block connector C-209 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-206 (terminal 4) and rear window defogger connector F-04 (terminal 1) in good condition?

YES: Replace the A/C-ECU. The rear window defogger should operate normally.

NO: Repair or replace the wiring harness. Check that the rear window defogger system works normally.

STEP 14. Measure at rear window defogger connector F-01 to check the ground circuit to the rear window defogger connector.




1. Disconnect rear window defogger connector F-01, and measure at the wiring harness side.




2. Measure the resistance value between terminal 1 and ground.
- The measured value should be 2 ohms or less.

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

YES: Go to Step 17.

NO: Go to Step 15.




STEP 15. Check rear window defogger connector F-01 for damage.

Q: Is rear window defogger connector F-01 in good condition?

YES: Go to Step 16.

NO: Repair or replace the connector. Check that the rear window defogger system works normally.




STEP 16. Check the wiring harness between rear window defogger connector F-01 (terminal 1) and ground.

Q: Is the wiring harness between 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 connector. Check that the rear window defogger system works normally.

STEP 17. Check the rear window defogger.

Refer Rear Window Defogger Switch Inspection in Windows and Glass/Heated Glass Element Switch.

Q: Does the rear window defogger work normally?

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 the rear window defogger.