GM Service Manual Online
For 1990-2009 cars only

Adjustment Procedure

    â€¢ Check the switch for proper operation.
    â€¢ 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.
    â€¢ Tighten the bolts and check the switch for proper operation.
    â€¢ Repeat the switch adjustment procedure until the engine starts when the shift lever is positioned in park and neutral.