I have one functional remote for my 2004 Express, and have purchased a second. Can I program this myself? I have read differing procedures, seems like GM might not have been consistent across all models? I don't want to mess up the working one that I have. I have read threads that discussed having 2 new remotes done by a dealer or locksmith, just hoping I might be able to do this myself, already having one that is currently programmed.

Thanks