GM Service Manual Online
For 1990-2009 cars only

Important: 

   • The following procedure is for vehicles that have not had the switch removed or replaced. If the switch has been removed or replaced, refer to Park/Neutral Position and Backup Lamp Switch Replacement for the proper adjustment procedure.
   • Apply the parking brake.
   • The engine must start in the P (PARK) or N (NEUTRAL) positions only.
   • Check the switch for proper operation. If adjustment is required, proceed as follows:

  1. Place the transmission range selector in the N (NEUTRAL) position.
  2. With an assistant in the drivers seat, raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
  3. Loosen the park/neutral position switch mounting bolts.
  4. With the vehicle in the N (NEUTRAL) position, rotate the switch while the assistant attempts to start the engine.
  5. Following a successful start, turn the engine OFF.
  6. Notice: Refer to Fastener Notice in the Preface section.

  7. Tighten the bolts securing the park/neutral back up switch to the transmission.
  8. Tighten
    Tighten the park/neutral back up switch bolts to 27 N·m (20 lb ft).

  9. Lower the vehicle.
  10. Check the switch for proper operation. The engine must start in the P (PARK) or N (NEUTRAL) positions only.
  11. Replace the park/neutral position switch if proper operation can not be achieved. Refer to Park/Neutral Position and Backup Lamp Switch Replacement .