The exact procedure might vary slightly depending on the specific trim level and any aftermarket modifications, but here's a general outline:
1. Steering Wheel Removal (Often Necessary): You'll likely need to remove the steering wheel to access the ignition switch. This usually involves removing the horn contact, the steering wheel retaining nut (often requiring a special tool), and potentially the steering column shroud. Be extremely cautious when removing the steering wheel, as the airbag (if equipped) can deploy unexpectedly. If you are unsure about this step, consult a repair manual specific to your truck's year and model.
2. Column Shroud Removal: Once the steering wheel is off, remove the steering column shroud or any plastic covers surrounding the ignition switch. This typically involves removing screws and potentially some clips.
3. Ignition Switch Access: With the shroud removed, you should now have visual access to the ignition switch. It will likely be held in place by screws or a retaining clip.
4. Wiring Harness Disconnection: Carefully disconnect the wiring harness from the ignition switch. Take photos or make notes of the wiring configuration before disconnecting anything to ensure correct reassembly. Labeling wires with tape is highly recommended.
5. Ignition Switch Removal: Remove the screws or clip holding the ignition switch in place and carefully remove it. The switch itself may be a single unit or comprised of several components.
6. Replacement (If Applicable): If replacing the switch, carefully install the new switch, ensuring all wiring connections are made correctly and securely. Refer to your wiring diagram or the instructions provided with the replacement part.
7. Reassembly: Reassemble the steering column shroud, steering wheel (making sure it's correctly aligned), and any other components you removed in reverse order.
Important Considerations:
* Repair Manual: A factory service manual specific to your 1990 Chevy half-ton pickup is highly recommended. It will provide detailed diagrams and instructions for this procedure, minimizing the risk of damage. You can find these online or at auto parts stores.
* Tools: You will need a variety of tools, including screwdrivers (Phillips and flathead), possibly a socket set, and potentially a steering wheel puller.
* Safety: Always disconnect the negative battery terminal before starting any electrical work. Be cautious when working around the steering column and airbag system (if equipped).
* Professional Help: If you're not comfortable performing this repair yourself, consider taking your truck to a qualified mechanic. Incorrectly installing the ignition switch can lead to further damage or even safety hazards.
This is a general guide. The specific steps may differ slightly based on your truck's model. Always consult a repair manual for your specific vehicle before beginning any repair work.
