I'm in the middle of a discussion on Facebook over the ESC module and when/where it's used. Used Rock Auto for reference and it spans '84-'95 over several models, several being the same platform (i.e. '94 C1500 pickup and C1500 Suburban). I see certain models have it for a specific year but others don't - case in point the '94 pickup/Suburban scenario... can someone explain?