Here's a general outline of the process. Specific steps and difficulty may vary slightly depending on your exact model and trim level. Always consult a repair manual specific to your 1990 Buick Century for detailed instructions and diagrams. A Haynes or Chilton manual would be extremely helpful.
Before You Begin:
* Disconnect the negative battery terminal. This is crucial to prevent electrical shocks and short circuits.
* Gather your tools: You'll need screwdrivers (Phillips and possibly flathead), possibly sockets and ratchets, pliers, and potentially a wiring diagram.
* Take pictures: Before disconnecting anything, take plenty of pictures of the wiring harness and its connections. This will be invaluable when reinstalling the new switch.
General Steps (Consult your repair manual for precise details):
1. Steering Wheel Removal (Possibly): In some cases, you might need to remove the steering wheel to access the ignition switch. This requires specialized tools and knowledge to avoid damaging the airbag (if equipped) and the steering column. If unsure, skip this step and consult a professional.
2. Column Shroud Removal: Remove the plastic shroud surrounding the steering column. This usually involves removing screws and possibly some trim pieces.
3. Wiring Harness Disconnection: Carefully disconnect the wiring harness from the old ignition switch. Again, take pictures! Label the wires if possible to avoid confusion during reassembly.
4. Ignition Switch Removal: The ignition switch is typically held in place by screws or a retaining clip. You'll need to access it from behind the steering column. This is often the most challenging part of the job. The switch may be part of a larger assembly, requiring careful disassembly.
5. Installation of the New Switch: Install the new ignition switch, ensuring it's securely fastened.
6. Wiring Harness Reconnection: Carefully reconnect the wiring harness to the new ignition switch, matching the wires exactly as they were before. Refer to your pictures and/or wiring diagram.
7. Reassembly: Reassemble the steering column shroud and steering wheel (if removed).
8. Reconnect the Battery: Reconnect the negative battery terminal.
9. Test: Test the ignition switch to ensure all positions (start, accessory, etc.) function correctly.
Important Considerations:
* Key: You will likely need your old key to remove the ignition switch and possibly to program the new one. Some ignition switches are keyed specifically to the vehicle's key. You might need a locksmith or dealer to have a new key cut or ignition switch programmed.
* Security Systems: If your Buick Century has an aftermarket or factory security system, be aware that disconnecting the battery and replacing the ignition switch could trigger it. You might need to reprogram or disarm the system afterward.
Again, this is a general overview. A repair manual specific to your 1990 Buick Century is crucial for success. If you're not comfortable with automotive repair, have a qualified mechanic perform this task. Improper installation could lead to electrical problems or even damage to your vehicle.
