GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

Important: The park/neutral position switch prevents starter motor operation when the automatic transmission control is in any gear by breaking the starter motor circuit. When the automatic transmission control is in (R) Reverse with the engine running, the park/neutral position switch completes the backup lamp circuit, lighting the backup lamps.

  1. Disconnect the negative battery cable. Refer to

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  2. Remove the front floor console. Refer to Instrument Panel, Gauges, and Console.

  3. Object Number: 38139  Size: SH
  4. Remove the park/neutral position switch bolts.

  5. Object Number: 38141  Size: SH
  6. Remove the park/neutral position switch.

Installation Procedure

Using The Old Switch

  1. Place the automatic transmission control in (N) Neutral.

  2. Object Number: 38142  Size: SH
  3. Install the tang on the switch, into the slot on the automatic transmission control.

  4. Object Number: 38139  Size: SH
  5. Loosely, install the bolts to the automatic transmission case.

  6. Object Number: 38144  Size: SH
  7. Insert a 2.34 mm (0.094 in) gage pin into the service adjustment hole. Rotate the switch until the gage pin drops to 15 mm (0.59 in) depth.
  8. Tighten
    Tighten the bolts to 2.2 N·m (19 lb in).

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  9. Install the front floor console. Refer to Instrument Panel, Gauges, and Console.
  10. Important: Ensure that the engine will only start in the (P) Park or the (N) Neutral position. Readjust the switch, if the engine will start in any other position.

  11. Connect the negative battery cable.
  12. Tighten
    Negative battery cable to 15 N·m (11 lb ft).

Using A New Switch

  1. Place the automatic transmission control in (N) Neutral.

  2. Object Number: 38142  Size: SH
  3. Install the tang on the switch, into the slot on the automatic transmission control.
  4. Important: Align the holes with the shift control. Place the shift control lever in (N) Neutral. Do not rotate the switch. The switch is pinned in the (N) Neutral position. If the switch has been rotated and the pin is broken, adjust the switch. Refer to Old Switch Installation.


    Object Number: 38139  Size: SH
  5. Install the bolts to the automatic transmission case.
  6. Tighten
    tighten the bolts to 2.2 N·m (19 lb in).

  7. Install the front floor console. Refer to Instrument Panel, Gauges, and Console.
  8. Important: Ensure that the engine will only start in the (P) Park or the (N) Neutral position. Readjust the switch if the engine will start in any other position. Refer to Old Switch Installation.

  9. Connect the negative battery cable.
  10. Tighten
    Negative battery cable to 15 N·m (11 lb ft).