I just purchased a 1997 Ford Ranger and I just found out about a quirky electrical thing. If I turn the headlight switch to the left, one click past off, I can turn the key off and remove it and keep the engine running. The radio and lights all go off, and the steering wheel locks, but the engine stays on. The only explanation that I can think of is I know the the truck was originally sold as a fleet vehicle and maybe this is a feature designed to secure the truck while making deliveries while not having to constantly stop the engine.
If anybody has any ideas, please let me know. I have been searching online for an answer and haven't gotten anywhere!