Rear Window Defogger System Does Not Operate
WINDOW / GLASS: WINDOW DEFOGGER SYSTEM: Rear Window Defogger System does not Operate
- Rear Window Defogger System does not Operate
DESCRIPTION
When the rear window defogger switch is turned on, a rear window defogger activation request signal is sent via the LIN communication line*1 or CAN communication line*2 to the air conditioning amplifier. Then the air conditioning amplifier operates the rear window defogger. When the on signal from the switch is received, the defogger relay (DEFOG) is operated for 15 minutes. Also, if the off signal from the switch is received within 15 minutes, the defogger relay (DEFOG) operation is stopped.
HINT
*1: w/o Multi-display
*2: w/ Multi-display
WIRING DIAGRAM
INSPECTION PROCEDURE
PROCEDURE
1. CHECK FOR DTC
(a) Check for DTC.
Result
C -- GO TO CAN COMMUNICATION SYSTEM CAN Communication System
B -- GO TO LIN COMMUNICATION SYSTEM LIN Communication System
A -- 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, A/C IG)
B -- REPLACE MULTI-DISPLAY
A -- Continue to next step.
3. REPLACE AIR CONDITIONING CONTROL ASSEMBLY
(a) Temporarily replace the air conditioning control assembly with a new or normally functioning one Removal.
NEXT -- Continue to next step.
4. CHECK WINDOW DEFOGGER SYSTEM
(a) Turn the engine switch on (IG).
(b) Check that pressing the defogger switch illuminates the indicator and warms the rear window surface.
(c) Check that after approximately 15 minutes, the indicator light turns off and the rear window defogger deactivates.
OK:
Rear window defogger system functioning normally.
NG -- REPLACE AIR CONDITIONING AMPLIFIER Removal
OK -- END (AIR CONDITIONING CONTROL ASSEMBLY IS DEFECTIVE)
5. REPLACE MULTI-DISPLAY
(a) Temporarily replace the multi-display with a new or normally functioning one Removal.
NEXT -- Continue to next step.
6. CHECK WINDOW DEFOGGER SYSTEM
(a) Turn the engine switch on (IG).
(b) Check that pressing the defogger switch illuminates the indicator and warms the rear window surface.
(c) Check that after approximately 15 minutes, the indicator light turns off and the rear window defogger deactivates.
OK:
Rear window defogger system functioning normally.
NG -- REPLACE AIR CONDITIONING AMPLIFIER Removal
OK -- END (MULTI-DISPLAY IS DEFECTIVE)
7. INSPECT FUSE (DEFOG, A/C IG)
(a) Remove the DEFOG fuse from the engine room junction block.
(b) Remove the A/C IG fuse from the main body ECU.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPLACE FUSE
OK -- Continue to next step.
8. INSPECT DEFOGGER RELAY (DEFOG)
(a) Remove the defogger relay from the engine room junction block.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPLACE DEFOGGER RELAY
OK -- Continue to next step.
9. CHECK HARNESS AND CONNECTOR (DEFOGGER RELAY - BATTERY AND AIR CONDITIONING AMPLIFIER)
(a) Remove the defogger relay from the engine room relay block.
(b) Disconnect the E36 air conditioning amplifier 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.
10. CHECK HARNESS AND CONNECTOR (REAR WINDOW DEFOGGER - DEFOGGER RELAY AND BODY GROUND)
(a) Disconnect the S17 and S18 defogger wire connectors.
(b) Remove the defogger relay from the engine room 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.
11. CHECK REAR WINDOW DEFOGGER WIRE
(a) Disconnect the S17 and S18 defogger wire connectors.
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
NG -- REPLACE AIR CONDITIONING AMPLIFIER Removal
OK -- REPLACE BACK WINDOW GLASS Removal