Classic/Antique Car Repair: Dome Light, ford mustang, dome light

Question
I have a 1966 Ford Mustang. The dome light does not work when the ignition is in the off position. When the ignition is in the start or accessory position the dome light works fine. What could be the problem?

Answer
It would appear that some where in it's past it was owned by some one that wanted to sit with a door open and not run the battery dead. And as such the dome light is wired through the ignition switch. Check the following web site for a wiring diagram for your car if you want to rewire it. www.metropartsmarket.com/catalog/classicmustangparts-c3s2.html.
Brad