1. Verify Connections:
* Battery: This is the most crucial first step. Check the battery terminals for corrosion and tightness. A loose or corroded connection can prevent the car from starting even if the ignition switch is working correctly. Clean the terminals with a wire brush and reconnect them securely. Also, check the battery voltage with a multimeter. It should be around 12.6V.
* Ignition Switch Connections: Carefully examine the wiring harness connected to the new ignition switch. Ensure all wires are properly seated and none are damaged or broken. Double-check the wiring diagram to ensure you connected each wire to the correct terminal on the switch. A single misplaced wire can cause a complete electrical failure.
* Other Connections: Look at any other connections near the ignition switch that might have been disturbed during the replacement.
2. Check for Blown Fuses:
* Ignition Fuse: Locate the fuse box (usually under the hood or under the dashboard) and check the fuse(s) specifically related to the ignition system. A blown fuse can prevent power from reaching the ignition switch and other components. Replace any blown fuses with fuses of the correct amperage.
3. Test the Ignition Switch Itself (If Possible):
* If you have a multimeter: Test the continuity and voltage at the different terminals of the ignition switch in various positions (accessory, run, start) to verify if it's actually working as expected. You'll need a wiring diagram for your specific vehicle to do this correctly.
4. Check the Neutral Safety Switch (Automatic Transmission):
* If your Impala has an automatic transmission, the neutral safety switch prevents the car from starting unless the gear selector is in Park or Neutral. A faulty neutral safety switch can completely disable the starter.
5. Anti-theft System:
* Some vehicles have anti-theft systems that can disable the car's electrical system if they detect a problem. If you are unsure whether your Impala has such a system, see your owners' manual.
6. Professional Help:
* If you've checked all the above and the car remains dead, it's time to seek professional help. An automotive electrician or mechanic will have the tools and expertise to diagnose the problem more accurately. They might use a scan tool to check for any error codes stored in the car's computer.
Important Note: Improper installation of the ignition switch can damage the car's electrical system. If you are not comfortable working with car electrical systems, it's best to have a qualified mechanic perform the repair. Working on automotive electrical systems can be dangerous. Incorrect connection can cause short-circuits and potential fire hazards.
