Here's a general outline. Specific details may vary slightly depending on your truck's trim and configuration. Always consult a repair manual specific to your 1986 GMC Sierra for detailed instructions and diagrams. A Haynes or Chilton manual is a good investment.
Steps (General):
1. Disconnect the Battery: This is crucial to prevent electrical shorts and injury. Disconnect the negative (-) terminal first.
2. Steering Wheel Removal (Possibly): Depending on how much access you need, you may need to remove the steering wheel. This requires special tools and careful attention to avoid damaging the airbag (if equipped, though unlikely on an '86). If you don't have experience, this step is best left to a professional.
3. Steering Column Shroud Removal: Remove the plastic or metal shroud that covers the steering column. This usually involves removing screws and possibly some trim pieces.
4. Ignition Switch Access: Once the shroud is off, you'll see the ignition switch. It's usually held in place by screws or a retaining clip. You might need to disconnect some wiring harnesses connected to the switch. Take pictures or make detailed notes before disconnecting anything! This is vital for reassembly.
5. Wiring Harness Disconnection: Carefully disconnect the electrical connectors from the ignition switch. Again, take pictures or detailed notes to ensure correct reconnection later. Labeling the wires with masking tape and a marker is a good idea.
6. Ignition Switch Removal: Remove the screws or clip holding the ignition switch in place. The switch itself might be slightly tricky to maneuver out, depending on its location and surrounding components.
7. Installation of New Ignition Switch: Carefully install the new ignition switch, making sure it's properly seated and aligned. Secure it with the screws or clip.
8. Wiring Harness Reconnection: Reconnect the electrical connectors to the new ignition switch, ensuring each wire goes to its correct location. Refer to your pictures or notes.
9. Steering Column Shroud Reinstallation: Reinstall the steering column shroud, ensuring all screws and clips are properly secured.
10. Steering Wheel Reinstallation (Possibly): If you removed the steering wheel, reinstall it carefully, ensuring it's properly aligned. This requires torqueing the nut to the correct specification.
11. Reconnect the Battery: Reconnect the negative (-) battery terminal.
12. Test the Ignition System: Turn the key to verify that the ignition system works correctly – starting, lights, etc.
Important Considerations:
* Key: You'll likely need the key from the old ignition switch to remove it.
* Security: Some ignition switches have security features. Make sure the replacement switch is compatible with your truck's security system, if applicable.
* Professional Help: If you are not comfortable with working on automotive electrical systems or removing the steering wheel, it's best to take your vehicle to a qualified mechanic. Incorrect installation can lead to electrical problems or damage to your vehicle.
This is a general guide. Refer to a repair manual specific to your 1986 GMC Sierra for accurate and detailed instructions. Always prioritize safety and take your time. Rushing the job can lead to errors and further complications.
