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Home >> Chevrolet >> 2006 >> Silverado 1500 HD, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1306 (Fixed & MOVEABLE Window System) >> Diagnostic Information and Procedures >> Rear Window Defogger Malfunction >> Circuit/System Verification

Circuit/System Verification

WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition ON, RPO CJ2, observe the scan tool Auto HVAC Rear Defrost Switch parameter while pressing the rear window defogger switch. The parameter should change between Active and Inactive.
    • If the parameter does not change between the commanded states, replace the HVAC module.
  2. RPO CJ3, observe the scan tool Manual HVAC Rear Defrost State parameter while pressing the rear window defogger switch. The parameter should change between On and Off.
    • If the parameter does not change between the commanded states, replace the HVAC module.
  3. Observe the operation of the rear window defogger indicator while pressing the rear window defogger switch. The 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 module.
  4. Command the rear window defogger ON and OFF with a scan tool. The rear window defogger should turn ON and OFF when changing between the commanded states.