Why does my driver side door say its open?

Hello.... I'm not sure what you mean by "hands-on" testing. Could you elaborate?

Physically using testing equipment to discover exactly what has failed.. Unfortunately testing procedures can’t be conveyed via online correspondence as it requires relative knowledge to perform and diagnostic literature to observe during the process. In other words it’s not recommended for the DIYer. https://repairpal.com/repair-shops/auto-repair-in-chicago-illinois Good luck!