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 rear window defogger switch turns ON, a rear defogger activation request signal from the air conditioning amplifier is sent via the CAN line to the front light ECU. Then the front light ECU operates the rear window defogger.
HINT
This circuit uses the CAN communication line. Before performing the inspection, check that the CAN communication system is functioning normally.
WIRING DIAGRAM
INSPECTION PROCEDURE
PROCEDURE
1. CHECK OPERATION (ENGINE START)
(a) Check that the engine starts normally.
OK:
Engine starts normally.
NG -- GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START Initial Inspection and Diagnostic Overview
OK -- Continue to next step.
2. PERFORM ACTIVE TEST USING TECHSTREAM (DEFOGGER RELAY)
(a) Select the Active Test, using the Techstream to generate a control command, and then check that the rear window defogger operates.
Air Conditioner
Result
C -- INSPECT FUSE (DEFOG, D-IG1-3)
B -- CHECK INTEGRATION CONTROL AND PANEL (OPERATION)
A -- Continue to next step.
3. CHECK DISPLAY AND NAVIGATION MODULE DISPLAY (OPERATION)
(a) Temporarily replace the display and navigation module display with a new or normally functioning one Removal.
(b) Check that the malfunction disappears.
OK:
Malfunction disappears.
Result
D -- REPLACE AIR CONDITIONING AMPLIFIER Removal
C -- REPLACE DISPLAY AND NAVIGATION MODULE DISPLAY Removal
B -- REPLACE DISPLAY AND NAVIGATION MODULE DISPLAY Removal
A -- REPLACE DISPLAY AND NAVIGATION MODULE DISPLAY Removal
4. CHECK INTEGRATION CONTROL AND PANEL (OPERATION)
(a) Temporarily replace the integration control and panel with a new or normally functioning one Removal.
(b) Check that the malfunction disappears.
OK:
Malfunction disappears.
NG -- REPLACE AIR CONDITIONING AMPLIFIER Removal
OK -- REPLACE INTEGRATION CONTROL AND PANEL Removal
5. INSPECT FUSE (DEFOG, D-IG1-3)
(a) Remove the DEFOG H-fuse from the engine room No. 1 relay block.
(b) Remove the D-IG1-3 fuse from the main body ECU.
(c) Measure the resistance of the fuses.
Standard resistance
NG -- REPLACE FUSE
OK -- Continue to next step.
6. INSPECT DEFOGGER RELAY (DEFOG)
(a) Remove the defogger relay from the relay block No. 3.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:
NG -- REPLACE DEFOGGER RELAY
OK -- Continue to next step.
7. CHECK HARNESS AND CONNECTOR (DEFOGGER RELAY - FRONT LIGHT ECU AND BATTERY)
(a) Remove the defogger relay from the No. 3 relay block.
(b) Disconnect the A51 front light ECU connector.
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:
(d) Measure the resistance according to the value(s) in the table below.
Standard resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
8. CHECK HARNESS AND CONNECTOR (REAR WINDOW DEFOGGER - DEFOGGER RELAY AND BODY GROUND)
(a) Disconnect the S19 and W1 defogger connectors.
(b) Disconnect the defogger relay from the No. 3 relay block.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
9. INSPECT REAR WINDOW DEFOGGER WIRE
(a) Turn the engine switch on (IG).
(b) Turn the defogger switch ON.
(c) Check 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.
NOTICE:
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.
(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 and gradually increase to approximately 12 V as the meter probe is moved to the other end.
NG -- REPAIR REAR WINDOW DEFOGGER WIRE Service and Repair
OK -- Continue to next step.
10. CHECK FRONT LIGHT ECU (OPERATION)
(a) Temporarily replace the front light ECU with a new or normally functioning one.
(b) Check that the malfunction disappears.
OK:
Malfunction disappears.
NG -- REPLACE AIR CONDITIONING AMPLIFIER Removal
OK -- REPLACE FRONT LIGHT ECU