Hey all, long time lurker, finally decided to join because there are a ton of very helpful and smart people on here! I bought a 03 Silverado 4wd w/Qsteer with 146k miles about 2 months ago. It had some delay shifting between 2nd and 3rd. I went ahead and took it in and had the tranny rebuilt and now it shifts great. Anyway, i for the life of me cannot figure out why my cruise doesn't work. It didn't work when i bought it. I've checked fuses and everything else i can think of. I found out today that my 3rd brake light doesn't work, could that make the cruise not work? I know the multi-function switch could be the issue, but I'd rather check everything else i can before i buy the switch only to find out the switch isn't the problem lol. Anyway, any help would be appreciated!! Thanks everyone and keep up the great work here!!

 

You should be able to find a diagnostic flow sheet for the cruise control as well as associated electrical schematics here:
https://mcdowellpubliclibrary.org/chilton-auto-repair/

Good