map light switch?

[73dartneedswork]

I'm confused on how the map light on my 73 Dart is supposed to function.
I'm currently only able to turn on the map light when the dome light is on.
I would think that I should be able to turn on the map light without the dome light needing to be on.
What way is it supposed to work?

 

['73 Root Beer]

Mine is the same. Silly I know. It would be boss to have that come on alone.

 

[TrailBeast]

Supply power to it off the ignition and it'll come on ANY time the switch is on with the car running.
Supply power off the battery, and it'll come on ANY time with the switch on period.

Th drawback to the second option is that it could accidentally end up on and kill the battery after a day.