LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2006 >> Cobalt LTZ >> Repair and Diagnosis >> External Pages >> Different car >> Section 728 (Fixed & MOVEABLE Window Systems) >> Diagnostic Information and Procedures >> Rear Window Defogger Malfunction >> Component Testing

Component Testing

WARNING: This page is about a different car, the 2008 Pontiac G5 and 2008 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.

Defog Switch

  1. Ignition OFF, disconnect the X2 harness connector at the HVAC control module.
  2. Test for infinite resistance between the signal terminal A8 and the ground terminal A5 with the switch in the open position.
    • If not the specified value, replace the HVAC control module.
  3. Test for less the 2 ohms between the signal terminal A8 and the ground terminal A5 with the switch in the closed position.
    • If greater than the specified range, replace the HVAC control module.

Defog Indicator

  1. Ignition OFF, disconnect the X2 harness connector at the HVAC control module.
  2. Install a 5-amp fused jumper wire between control terminal A7 and 12 volts. Install a jumper wire between the ground terminal A5 and ground. Verify the defog Indicator illuminates.
    • If the defog indicator does not illuminate, replace the HVAC control module.

Rear Window Defogger Grid Test

  1. Ignition ON, turn on the rear window defogger.
  2. Verify that a test lamp illuminates between each rear window defogger grid line and ground. The test lamp should be off when testing at the ground side of the grid and get brighter as the test lamp moves closer to the voltage supply side of the grid. The test lamp should be dim when testing each grid line in the middle.
    • If the test lamp remains bright at the middle of the grid line, test for an open between the test point and the ground side of the grid.
    • If the test lamp remains off at the middle of the grid line, test for an open between the test point and the voltage supply side of the grid

Relay Test

  1. Ignition OFF, disconnect the REAR DEFOG relay.
  2. Test for 60-180 ohms between terminals 85 and 86.
    • If not within the specified range, replace the relay.
  3. Test for infinite resistance between the following terminals:
    • 30 and 86
    • 30 and 87
    • 30 and 85
    • 85 and 87
    • If not the specified value, replace the relay.
  4. Install a 25-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.
    • If greater than the specified range, replace the relay.
scientia non olet · About LEMON Manuals