INSPECTION PROCEDURE 8: The rear window defogger does not work














COMMENTS ON TROUBLE SYMPTOM
If the rear window defogger does not work after switching on (the defogger timer will be on for approximately 20 minutes), the rear window defogger relay circuit may be defective.
note When the engine is not running, the rear window defogger does not work.

PROBABLE CAUSES

  • Malfunction of the rear window defogger relay
  • Wiring harness or connector failure
  • Malfunction of A/C control panel

DIAGNOSTIC PROCEDURE

STEP 1. Check that the inside air/outside air recirculation can be switched.
Check that the inside air/outside air recirculation can be switched normally.

Q. Is the check result normal?
Go to Step 2.
INSPECTION PROCEDURE 14: Refer to "A/C-ECU power supply system" .

STEP 2. M.U.T.-III diagnosis code
Check that the air conditioner has not set a diagnosis code.

Q. Is the diagnosis code set?
Carry out the diagnosis code procedures. Refer to .
Go to Step 3.

STEP 3. M.U.T.-III other system’s diagnosis code
Check that the ETACS-ECU has not set a diagnosis code.

Q. Is the diagnosis code set?
Carry out the diagnosis code procedures. Refer to GROUP 54A, ETACS-ECU .
Go to Step 4.

STEP 4. Connector check: C-306 rear window defogger relay connector

Q. Is the check result normal?
Go to Step 5.
Repair the connector concerned.

STEP 5. Check the rear window defogger relay.
Refer to GROUP 54A - Defogger .

Q. Is the check result normal?
Go to Step 6.
Replace the defogger relay.

STEP 6. Connector check: F-24 rear window defogger connector

Q. Is the check result normal?

    Go to Step 7.
Repair the connector concerned.

STEP 7. Measure the voltage at F-24 rear window defogger connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Ignition switch: ON
(3)Rear window defogger switch: ON (measure within 20 seconds after the switch is turned on)
(4)Voltage between terminal 1 and body earth
OK: Battery voltage

Q. Is the check result normal?
Go to Step 8.
Go to Step 9.

STEP 8. Measure the resistance at F-06 rear window defogger connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Resistance between terminal 1 and body earth
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?
Repair the rear window defogger (Refer to GROUP 54A - Rear Window Defogger ).
Repair the wiring harness wires between F-05 rear window defogger connector terminal No. 1 and body earth.

STEP 9. Measure the voltage at C-306 rear window defogger connector.
(1)Remove the relay, and measure at the junction block side.
(2)Ignition switch: ON
(3)Voltage between terminal 4 and body earth
OK: Battery voltage

Q. Is the check result normal?
Go to Step 11.
Go to Step 10.

STEP 10. Check the wiring harness between C-306 rear window defogger relay connector terminal No. 4 and fusible link (38) connector.

  • Check the power supply line for open circuit.

Q. Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
Repair the wiring harness.

STEP 11. Measure the voltage at C-306 rear window defogger connector.
(1)Remove the relay, and measure at the junction block side.
(2)Voltage between terminal 1 and body earth
OK: Battery voltage

Q. Is the check result normal?
Go to Step 14.
Go to Step 12.

STEP 12. Connector check: C-301 ETACS-ECU connector

Q. Is the check result normal?
Go to Step 13.
Repair the connector.

STEP 13. Check the wiring harness between C-309 rear window defogger relay connector terminal No. 1 and C-301 ETACS-ECU connector terminal No. 12.

  • Check the power supply line for open circuit.

Q. Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
Repair the wiring harness.

STEP 14. Connector check: C-120 A/C control panel connector

Q. Is the check result normal?
Go to Step 15.
Repair the connector.

STEP 15. Check the wiring harness wires between C-306 rear window defogger relay connector terminal No. 2 and C-120 A/C control panel connector terminal No. 6.

  • Check the input line for open or short circuit.

Q. Is the check result normal?
Go to Step 16.
Repair the wiring harness.

STEP 16. Check the wiring harness wires between C-306 rear window defogger relay terminal No. 3 and F-24 rear window defogger connector terminal No. 1.

  • Check the input line for open circuit.
note Prior to the wiring harness inspection, check intermediate connectors C-36 and D-12, and repair if necessary.

Q. Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
Repair the wiring harness.