GM Service Manual Online
For 1990-2009 cars only
  1. Before attempting any electrical diagnosis, verify that the sunroof does not bind due to a mechanical failure.
  2. Visually inspect the sunroof fuse.
  3. Verify that ground G401 is clean and tight.
  4. Refer to the power sunroof and related component repair procedures in order to access the power sunroof.
  5. Inspect for a broken (or partially broken) wire inside of the insulation.
  6. A broken wire inside of the insulation may cause a system failure but prove good in a continuity/voltage test.

  7. Inspect for proper installation of the aftermarket electronic equipment.
  8. Improper installation of all the aftermarket electronic equipment may affect the integrity of other systems. Refer to Power Sunroof Does Not Open .