GM Service Manual Online
For 1990-2009 cars only
  1. Check the switch for proper operation.
  2. The engine must be in the P (Park) or N (Neutral) positions only. If adjustment is required, loosen the switch retaining bolts and rotate the switch slightly.
  3. Tighten the bolts and check the switch for proper operation.
  4. Repeat the switch adjustment procedure until the engine starts when the shift lever is positioned in park and neutral.