'02 Suburban issues

[Donaldo]

Hi, I usually hang out on the earlier Chevy truck list, building a '51 3100. My Suburban is having some intermittent sensor issues, gas gauge reads low, washer fluid reads low and it seems the a/c is on whenever I use any of the air supply indicators. And the Change oil light is on a lot of the time too, even after oil changes.. Is there a computer that runs all of those features and is it much of a job to diagnose and replace ?

thanks, Don.