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 multiplex network front light ECU (front controller). Then the multiplex network front light ECU (front controller) operates the rear window defogger.
WIRING DIAGRAM
INSPECTION PROCEDURE
Note
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
Tech Tips
This circuit uses the CAN communication line. Before performing the inspection, check that the CAN communication system is functioning normally.
PROCEDURE
PERFORM ACTIVE TEST USING GTS (DEFOGGER RELAY [REAR])
Select the Active Test, using the GTS to generate a control command, and then check that the rear window defogger operates Click here.
| Tester Display | Test Part | Control Range | Diagnostic Note |
|---|---|---|---|
| Defogger Relay (Rear) | DEFOG relay operation | OFF / ON | - |
| OK |
|---|
| Rear window defogger operates normally |
| NG |
|
INSPECT DEFOG RELAY Click here |
| OK |
|
CHECK AIR CONDITIONING AMPLIFIER
Temporarily replace the air conditioning amplifier with a new or normally functioning one Click here.
Check that the malfunction disappears.
| OK |
|---|
| Malfunction disappears. |
| NG |
|
CHECK MULTIPLEX NETWORK FRONT LIGHT ECU Click here |
| OK |
|
END (AIR CONDITIONING AMPLIFIER IS DEFECTIVE)
CHECK MULTIPLEX NETWORK FRONT LIGHT ECU
Temporarily replace the multiplex network front light ECU (front controller) with a new or normally functioning one.
Check that the malfunction disappears.
| OK |
|---|
| Malfunction disappears. |
| NG |
|
REPLACE MULTI-MEDIA MODULE RECEIVER ASSEMBLY Click here |
| OK |
|
END (MULTIPLEX NETWORK FRONT LIGHT ECU [FRONT CONTROLLER] IS DEFECTIVE)
INSPECT DEFOG RELAY
Remove the DEFOG relay from the relay block No. 3.
Measure the resistance according to the value(s) in the table below.
| Standard resistance | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| NG |
|
REPLACE DEFOG RELAY |
| OK |
|
CHECK HARNESS AND CONNECTOR (DEFOG RELAY - MULTIPLEX NETWORK FRONT LIGHT ECU [FRONT CONTROLLER] AND BATTERY)
Remove the DEFOG relay from the No. 3 relay block.
Disconnect the A51 multiplex network front light ECU (front controller) connector.
Measure the voltage according to the value(s) in the table below.
| Standard voltage | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
Measure the resistance according to the value(s) in the table below.
| Standard resistance | ||||||
|---|---|---|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
| OK |
|
CHECK HARNESS AND CONNECTOR (BACK WINDOW GLASS - DEFOG RELAY AND BODY GROUND)
Disconnect the S19 and W1 back window glass connectors.
Disconnect the DEFOG relay from the No. 3 relay block.
Measure the resistance according to the value(s) in the table below.
| Standard resistance | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
| OK |
|
INSPECT BACK WINDOW GLASS
Inspect the back window glass Click here.
| Result | Proceed to |
|---|---|
| Rear window defogger is broken | A |
| Rear window defogger is not broken | B |
| B |
|
CHECK MULTIPLEX NETWORK FRONT LIGHT ECU (FRONT CONTROLLER) Click here |
| A |
|
REPAIR OR REPLACE BACK WINDOW GLASS Click here
CHECK MULTIPLEX NETWORK FRONT LIGHT ECU (FRONT CONTROLLER)
Temporarily replace the multiplex network front light ECU (front controller) with a new or normally functioning one.
Check that the malfunction disappears.
| OK |
|---|
| Malfunction disappears. |
| NG |
|
REPLACE AIR CONDITIONING AMPLIFIER Click here |
| OK |
|
END (MULTIPLEX NETWORK FRONT LIGHT ECU [FRONT CONTROLLER] IS DEFECTIVE)