Tools You'll Likely Need:
* Socket set: Various sizes, including those for the steering column bolts and possibly the ignition switch retaining screws.
* Screwdrivers: Phillips and possibly flathead.
* Pliers: Needle-nose pliers might be helpful for small parts.
* Wrench: Possibly needed depending on the type of fasteners.
* Ignition switch removal tool: While not always necessary, this specialized tool makes removing the switch cylinder much easier. You can often find these at auto parts stores.
* New ignition switch assembly: Ensure you get the correct part for your specific truck model and year.
* Electrical tape (optional): For securing wires if necessary.
* Pen and paper: To record wire positions before disconnecting them.
Steps (General Outline - Refer to your repair manual for precise details):
1. Disconnect the Battery: This is the most crucial step to prevent electrical shocks and short circuits. Disconnect both negative (-) and positive (+) terminals.
2. Steering Column Access: You'll likely need to remove or at least partially remove the steering column shrouds/covers to access the ignition switch. This often involves removing screws and possibly detaching some trim pieces. Refer to your repair manual for precise instructions on how to do this for your specific model.
3. Steering Wheel Lock (if applicable): If the steering wheel is locked, you may need to manipulate it slightly to unlock it. This usually involves gently jiggling the wheel while turning the ignition key.
4. Remove the Ignition Switch Cylinder: This is usually the first step. It's usually retained by a retaining clip or screw; the ignition switch removal tool will make this process significantly easier. Carefully note the position and orientation of the cylinder. Take pictures if necessary.
5. Locate and Disconnect Wiring Harness: The wiring harness connecting to the ignition switch is usually secured with a retaining clip or screws. Before disconnecting anything, carefully draw a diagram or take photos showing the wire connections. This is vital for proper reassembly. Label the wires if you have multiple connections. Gently unclip the harness.
6. Remove the Ignition Switch Assembly: Once the wiring harness is disconnected, the ignition switch assembly itself may be secured with screws or bolts. Carefully remove these fasteners.
7. Install the New Ignition Switch Assembly: This is the reverse of the removal process. Follow the same steps you took for removal, but in reverse order. Pay close attention to wire placement. Ensure that all wires are properly seated and that the switch is correctly aligned in its mounting location.
8. Reconnecting the Wiring Harness: Carefully connect the wiring harness to the new ignition switch, ensuring that all wires are connected to their correct locations according to your diagrams or photos.
9. Install the Ignition Switch Cylinder: Reinstall the ignition switch cylinder, ensuring it is seated correctly and secured.
10. Reassemble the Steering Column: Put back the steering column shrouds/covers you removed earlier.
11. Reconnect the Battery: Carefully reconnect the battery terminals.
12. Test the Ignition System: Try the ignition key to ensure the new switch works correctly and that the vehicle starts. Test all ignition positions (accessory, on, start).
Important Considerations:
* Professional Help: If you're not comfortable with automotive repair, it's always best to seek professional help from a qualified mechanic.
* Repair Manual: A repair manual specific to your vehicle is invaluable. It provides detailed instructions, diagrams, and torque specifications crucial for successful repair.
* Safety First: Always prioritize safety. Disconnect the battery before starting any work. Wear safety glasses and gloves.
This is a general guide; the specifics might vary slightly depending on your particular 1990 Chevy half-ton truck model. Always consult your repair manual for the most accurate and safe procedure.
