WARNING: Before beginning, disconnect the negative battery terminal to prevent accidental shorts and injury.
General Steps:
1. Steering Column Removal (Partial or Full): This is usually necessary. You'll likely need to remove the steering wheel (requiring a steering wheel puller – rent or borrow one). Then, you'll need to access the ignition switch housing. This often involves removing parts of the steering column shroud, perhaps even some linkage components. The exact method varies significantly between trucks. A repair manual is critical here.
2. Accessing the Ignition Switch: Once the column is partially or fully disassembled, you'll locate the ignition switch. It's typically held in place by screws or a retaining clip.
3. Wiring Harness: Carefully disconnect the wiring harness from the ignition switch. Take pictures or make a detailed diagram *before* disconnecting anything to help you reconnect it correctly. Note the color coding of wires – crucial for proper reassembly.
4. Removing the Switch: Once the wiring is disconnected, remove the screws or release the clip securing the ignition switch to the steering column. Remove the old switch.
5. Installing the New Switch: Install the new ignition switch, ensuring it's properly seated and secured.
6. Reconnect the Wiring Harness: Reconnect the wiring harness, carefully matching the wire colors to your diagram or pictures. Double and triple-check your connections.
7. Reassembly: Reassemble the steering column and steering wheel, following the reverse order of disassembly.
8. Test: Reconnect the battery negative terminal and test the ignition switch to ensure it functions correctly.
Crucial Considerations:
* Repair Manual: A factory service manual or a Haynes/Chilton manual specific to your 1972 Chevy pickup is *absolutely essential*. These manuals provide detailed instructions with diagrams, making the job significantly easier and less prone to errors.
* Safety: Work in a well-lit area. Use appropriate tools. If you're uncomfortable with any part of the process, seek professional help from a mechanic. Improper reassembly can lead to serious problems, including driving issues and even safety hazards.
* Parts: Ensure you purchase the correct replacement ignition switch for your specific truck model.
* Variations: 1972 Chevy pickups had variations in their steering column assemblies. The exact procedure will depend on your truck's trim level and features.
Without a repair manual, providing precise instructions is impossible and potentially dangerous. Invest in the manual; it will save you time, frustration, and potential damage to your vehicle.
