Inspection Procedure 7

Defroster Function Does Not Operate.

Rear Window Defogger Circuit Part 1:

Rear Window Defogger Circuit Part 2:

TECHNICAL DESCRIPTION (COMMENT)
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 heater control
- Malfunction of the rear window defogger relay
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector.

DIAGNOSIS

Required Special Tools:
- MB991223: Test Harness Set

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 9 "Malfunction of the heater control Power Supply system".

STEP 2. Measure the voltage at rear window defogger connector F-16.




1. Disconnect rear window defogger connector F-16, and measure the voltage at the junction block side.
2. Turn the ignition switch to the "ON" position.
3. Turn the rear window defogger 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: Is the measured voltage approximately 12 volts?

YES: Go to Step 14.

NO: Go to Step 3.







STEP 3. Check the rear window defogger relay continuity.
Follow the table to check the rear window defogger relay for continuity.

Q: Is the rear window defogger relay 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-215.




1. Disconnect rear window defogger relay connector C-215, 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: Is the measured voltage approximately 12 volts?

YES: Go to Step 7.

NO: Go to Step 5.




STEP 5. Check rear window defogger relay connector C-215 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is rear window defogger relay connector C-215 in good condition?

YES: Go to Step 6.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. The rear window defogger system should work normally.







STEP 6. Check the wiring harness between rear window defogger relay connector C-215 (terminal 5) and the battery.

NOTE: Also check junction block connector C-212 and intermediate connector C-126 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If junction block connector C-212 and intermediate connector C-126 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-215 (terminal 5) and the battery in good condition?

YES: It can be assumed that this malfunction is intermittent. Refer to 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-215.




1. Disconnect rear window defogger relay connector C-215, 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: Is the measured voltage approximately 12 volts?

YES: Go to Step 10.

NO: Go to Step 8.




STEP 8. Check rear window defogger relay connector C-215 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is rear window defogger relay connector C-215 in good condition?

YES: Go to Step 9.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. Check that the rear window defogger system works normally.




STEP 9. Check the wiring harness between rear window defogger relay connector C-215 (terminal 1) and ignition switch (IG2).

NOTE: Also check junction block connector C-211 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If junction block connector C-211 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-215 (terminal 1) and ignition switch (IG2) in good condition?

YES: It can be assumed that this malfunction is intermittent. Refer to 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-215 and rear window defogger connector F-16 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are rear window defogger relay connector C-215 and rear window defogger connector F-16 in good condition?

YES: Go to Step 11.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. Check that the rear window defogger system works normally.







STEP 11. Check the wiring harness between rear window defogger relay connector C-215 (terminal 4) and rear window defogger connector F-16 (terminal 1).

NOTE: Also check junction block connector C-217 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If junction block connector C-217 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-215 (terminal 4) and rear window defogger connector F-16 (terminal 1) in good condition?

YES: Go to Step 12.

NO: Repair or replace the wiring harness. Refer to Harness Connector Inspection. Check that the rear window defogger system works normally.







STEP 12. Check rear window defogger relay connector C-215 and heater control connector C-16 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are rear window defogger relay connector C-215 and heater control connector C-16 in good condition?

YES: Go to Step 13.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. Check that the rear window defogger system works normally.







STEP 13. Check the wiring harness between rear window defogger relay connector C-215 (terminal 3) and heater control connector C-16 (terminal 1).

NOTE: Also check junction block connector C-214 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If junction block connector C-214 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-215 (terminal 3) and heater control connector C-16 (terminal 1) in good condition?

YES: Replace the heater control. The rear window defogger should operate normally.

NO: Repair or replace the wiring harness. Refer to Harness Connector Inspection. Check that the rear window defogger system works normally.

STEP 14. Measure at rear window defogger connector F-06 in order to check the ground circuit to the rear window defogger connector.




1. Disconnect rear window defogger connector F-06, 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-06 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is rear window defogger connector F-06 in good condition?

YES: Go to Step 16.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. Check that the rear window defogger system works normally.




STEP 16. Check the wiring harness between rear window defogger connector F-06 (terminal 1) and ground.

Q: Is the wiring harness between rear window defogger connector F-06 (terminal 1) and ground in good condition?

YES: It can be assumed that this malfunction is intermittent. Refer to How to Cope with intermittent Malfunctions.

NO: Repair or replace the wiring harness. Refer to Harness Connector Inspection. Check that the rear window defogger system works normally.

STEP 17. 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.
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: Check that the rear window defogger system works normally.

NO: Repeat from Step 1.