Envoy 4WD V8-5.3L VIN M (2005)
Heated Glass Element: Description and Operation
Rear Window Defogger
REAR WINDOW DEFOGGER DESCRIPTION AND OPERATION
REAR WINDOW DEFOGGER SYSTEM COMPONENTS
The rear window defogger system consist of the following components:
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HVAC control module
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Liftgate module (LGM)/endgate module (EGM)
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Rear window defogger grid
REAR WINDOW DEFOGGER OPERATION (WITH LGM)
Battery positive voltage is supplied through the LGM 2 fuse to the LGM for the rear window defogger system. When the rear window defogger switch
is depressed, the HVAC control module illuminates the rear window defogger indicator, and sends a class 2 message to the LGM to enable the rear
window defogger. The LGM enables the rear window defogger by allowing battery positive voltage to the rear window defogger.
When the rear window defogger switch is pressed for the first time, the defogger cycle lasts 10 minutes. Further operation results in 10 minute
defogger cycles.
REAR WINDOW DEFOGGER OPERATION (WITH EGM)
Battery positive voltage is supplied through the EGM 2 fuse to the EGM for the rear window defogger system. When the rear window defogger switch
is depressed, the HVAC control module illuminates the rear window defogger indicator, and sends a class 2 message to the EGM to enable the rear
window defogger. The EGM enables the rear window defogger by allowing battery positive voltage to the rear window defogger.
The following conditions must be met for rear window defogger to operate:
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The end gate glass position is not below the index position.
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The window express down movement is not requested.
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The window down movement is not requested.
If the end-gate glass is not fully closed, the DIC displays "Tailgate Glass Down" when the rear defogger operation is attempted.
When the rear window defogger switch is pressed for the first time, the defogger cycle lasts 10 minutes. Further operation results in 10 minute
defogger cycles.
