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Home >> Chevrolet >> 2011 >> Caprice >> Repair and Diagnosis >> Body & Frame >> Fixed And MOVEABLE Windows >> Diagnostic Information and Procedures >> Rear Window Defogger Malfunction >> Circuit/System Testing

Circuit/System Testing

  1. Ignition OFF, disconnect the KR5 rear defogger relay.
  2. Test for less than 10 Ω between the ground circuit terminal 85 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify a test lamp does not illuminate between the control circuit terminal 30 and ground.
    • If the test lamp illuminates, test the control circuit for a short to voltage.
  4. Verify a test lamp illuminates between the B+ circuit terminal 87 and ground.
    • If the test lamp does not illuminate and the B+ fuse is open, test the control circuit terminal 30 for a short to ground. If the circuit tests normal, test or replace the KR5 rear defogger relay.
  5. Ignition OFF, disconnect the X2 harness connector at the E18 rear defogger grid.
  6. Test for less than 5 Ω between the ground circuit terminal A and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect the X2 harness connector at the E18 rear defogger grid.
  8. Ignition ON, connect a 40 A fused jumper wire between the B+ circuit terminal 87 and the control circuit terminal 30. Verify the E18 rear defogger grid is activated.
    • If the E18 rear defogger grid does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the rear defogger grid.
  9. Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.
  10. Command the rear window defogger ON and OFF with a scan tool, the test lamp should turn ON and OFF when changing between the commanded states.
    • If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K33 HVAC control module.
    • If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K33 HVAC control module.
  11. If all circuits test normal, test or replace the KR5 rear defogger relay.
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