Savana 3500 V8-4.8L (2009)
Heated Glass Element: Testing and Inspection
Rear Window Defogger Malfunction
Diagnostic Instructions
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Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
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Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
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Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure Instructions)
provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
When the rear defogger button is pressed, voltage is supplied to the relay coil and the HVAC control assembly also illuminates the rear window defogger
indicator. Battery positive voltage is supplied at all times to the relay switched input and the relay coil is always grounded. This allows battery positive
voltage from the relay switched input through the switch contacts and out the relay switched output to the rear window defogger grids.
Reference Information
Schematic Reference
Defogger Schematics (See: Diagrams/Electrical Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Rear Window Defogger Description and Operation (See: Windows/Description and Operation/Rear Window Defogger Description and Operation)
Electrical Information Reference
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Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics)
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Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics)
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Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics)
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Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics)
Circuit/System Verification
Ignition ON, command the rear window defogger ON and OFF by pressing the rear window defogger switch. The rear window defogger and rear
window defogger indicator should turn ON or OFF each time the rear window defogger switch is pressed.
If the indicator does not turn ON or OFF with each switch press, replace the HVAC control assembly.
If a rear window defogger grid does not turn ON and OFF when changing between the commanded states, refer to Single Rear Window Defog Grid
Malfunction.
If both rear window defogger grids do not turn ON and OFF when changing between the commanded states, refer to Rear Window Defogger
Malfunction.