Rear Window Defogger System Does Not Operate

WINDSHIELD / WINDOWGLASS: WINDOW DEFOGGER SYSTEM: Rear Window Defogger System does not Operate

Rear Window Defogger System does not Operate

DESCRIPTION

When the A/C amplifier defogger switch is pressed, a signal is sent via the BEAN line to the luggage room junction block ECU. Then the luggage room junction block ECU operates the rear window defogger.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (REAR WINDOW DEFOGGER WIRE)
(a) Select the Active Test, use the Techstream to generate a control command, and then check the rear window defogger wire.

Body No. 4





OK:
Rear window defogger wire operates.
OK -- REPLACE LUGGAGE ROOM JUNCTION BLOCK ASSEMBLY (LUGGAGE ROOM JUNCTION BLOCK ECU)
NG -- Continue to next step.
2. INSPECT FUSE (DEFOG)
(a) Remove the DEFOG M-fuse from the luggage room junction block.
(b) Measure the resistance of the fuse.
Standard resistance:
Below 1 Ohms
NG -- REPLACE FUSE
OK -- Continue to next step.
3. INSPECT DEFOGGER RELAY (Marking: DEFOG)




(a) Remove the DEFOG relay from the luggage room junction block.
(b) Measure the resistance of the relay.
Standard resistance:






NG -- REPLACE DEFOG RELAY
OK -- Continue to next step.
4. CHECK WIRE HARNESS (LUGGAGE ROOM JUNCTION BLOCK - BATTERY)




(a) Disconnect the 6L junction block connector.
(b) Measure the voltage of the wire harness side connector.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
5. CHECK WIRE HARNESS (LUGGAGE ROOM JUNCTION BLOCK - REAR WINDOW DEFOGGER WIRE)




(a) Disconnect the 6D junction block connector.
(b) Disconnect the R12 defogger connector.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
6. CHECK WIRE HARNESS (REAR WINDOW DEFOGGER WIRE - BODY GROUND)




(a) Disconnect the R13 defogger connector.
(b) Measure the resistance of the wire harness side connector.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
7. INSPECT REAR WINDOW DEFOGGER WIRE




NOTICE:
- When cleaning the glass, wipe the glass along the wire using a soft and dry cloth. Take care not to damage the wires.
- Do not use detergents or glass cleaners that have abrasive ingredients.
- When measuring voltage, wrap a piece of tin foil around the tip of the negative tester probe and press the foil against the wire with your finger, as shown in the illustration.




(a) Turn the ignition switch ON.
(b) Turn the defogger switch ON.
(c) Measure the voltage at the center of each defogger wire as shown in the illustration.
Standard voltage:





HINT: If there is approximately 10 V, the wire may be faulty between the center of the wire and the wire end on the battery side. If there is no voltage, the wire may be faulty between the center of the wire and the wire end on the ground side.




(d) Place the voltmeter's positive (+) lead against the defogger wire on the battery side.
(e) Place the voltmeter's negative (-) lead with the foil strip against the wire on the ground side.
(f) Slide the positive (+) lead from the battery side to the ground side.
(g) The point where the voltage drops from approximately 10 V to 0 V is where the defogger wire is broken.
HINT: If the defogger wire is not broken, the voltmeter should indicate 0 V at the positive (+) end of the defogger wire. The voltage gradually increases to approximately 12 V as the lead moves to the other end.

NG -- REPAIR REAR WINDOW DEFOGGER WIRE
OK -- Continue to next step.
8. CHECK OPERATION OF A/C AMPLIFIER ASSEMBLY
(a) After replacing the A/C amplifier with a new one, check that the rear defogger operates normally.
OK:
Rear defogger operates normally.
NG -- GO TO LUGGAGE ROOM JUNCTION BLOCK ECU POWER
SOURCE CIRCUIT
OK -- END (A/C AMPLIFIER ASSEMBLY DEFECTIVE)