How do you replace ign lock cly on 1999 gmc pickup key will not turn?

1. Set the front wheels in the straight-ahead position.
2. Set the steering wheel in the LOCK position.
3. Disconnect the negative battery cable.

Caution: When you are performing service on or near the SIR components or the SIR wiring, you must disable the SIR system. Failure to follow the correct procedure could cause air bag deployment, personal injury, or unnecessary SIR system repairs.

1. Disable the Supplemental Inflatable Restraint (SIR) system. See: Air Bag(s) Arming and Disarming\Service and Repair\Disabling the SIR System
2. Remove the tilt lever.
3. Remove the 2 TORX head screws from the lower steering column shroud.
4. Remove the lower steering column cover shroud from the column.
5. Remove the TORX head screw from the upper steering column shroud.
6. Remove the upper steering column shroud from the column.

1. Turn the ignition lock cylinder to the START position.
2. Using an awl, insert the tip into the ignition lock cylinder access hole (1).
3. Push down and hold the ignition lock cylinder retaining pin.
4. Release the ignition lock cylinder to the RUN position.
5. Remove the ignition lock cylinder by pulling the ignition lock cylinder away from the steering column (2).

INSTALLATION PROCEDURE

1. Install the ignition lock cylinder into the steering column (2) using the following procedure:

1.1.Align the positioning locking tab slot on the lock module assembly to the positioning tab on the ignition lock cylinder.1.2.Push the lock cylinder in until the locking tab locks in the lock module assembly.

1. Install the upper steering column shroud to the steering column.
2. Install the TORX head screw to the upper steering column shroud.

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.

• Tighten the screw to 1.5 Nm (115 inch lbs.) .

1. Install the lower steering column shroud to the steering column.
2. Install the tilt lever.
3. Install the TORX head screws to the lower steering column shroud.

• Tighten the screws to 3 Nm (25 inch lbs.) .