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Home >> Chevrolet >> 2013 >> Sonic RS, Automatic Trans >> Repair and Diagnosis >> Body & Frame >> Windows >> Fixed And MOVEABLE Window System >> Diagnostic Information and Procedures >> Rear Window Defogger Malfunction >> Circuit/System Verification

Circuit/System Verification

  1. Engine running.
  2. Verify the scan tool Rear Defogger Switch parameter changes between Active and Inactive when pressing the rear window defogger switch.
    • If the parameter does not change between Active and Inactive 

      Replace the K33 HVAC control module.

    • If the parameter changes between Active and Inactive 
  3. Verify the E18 Rear Defogger Grid turns ON and OFF when pressing the rear window defogger switch.
    • If the E18 Rear Defogger Grid turns ON and OFF 
  4. Verify the rear window defog indicator turns ON and OFF when commanding the Illuminate All Indicators On and Off with a scan tool.
    • If the rear window defog indicator does not turn ON and OFF 

      Replace the K33 HVAC control module.

    • If the rear window defog indicator turns ON and OFF 
  5. All OK.
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