Could someone tell me how to replace an ignition switch on a 2003 Chevy Silverado? I replaced one on a 1975 Chevy, but I know there is probley a big difference. Thanks

First, disconnect the negative battery cable. One connector should plug into the main electrical harness, the other connector should plug into the underdash fuse box. It should be pretty straight-forward and what you are used to.

Here's my write-up on how to do it for a Honda--your Chevy should be similar:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-2.html#post224652