Some Electrical Help Please...

I have this little 63 Dart 4 door I am trying to finish up for James. One of the last things I need to address is the dome light comes on with the headlights. I'm assuming somehow that circuit is getting ground, since that's how it's switched at the doors, but my electrical diagnostic skills are not "that great". Any help is appreciated.
I noticed some of the aftermarket switches have a little connector on it that's a ground for that. That lasts little nudge when you turn it to the left just activates a ground... Also maybe make sure the headlight switch is grounded itself like if it's a freshly painted car or something it may not be making contact with the dash...