GM Service Manual Online
For 1990-2009 cars only
  1. Visually inspect the power mirror fuse.
  2. Refer to repair procedures in order to access the power mirror switch.
  3. Verify that ground G301 is clean and tight.
  4. Verify that the power mirror select switch is in the LEFT position or the RIGHT position and not the center OFF position.
  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 aftermarket electronic equipment affects the integrity of other systems.