dome light wire runs across the middle roof support toward drivers side- is connected with the welded on wire clips on the roof support. The wire thenruns down along inner roof line on drivers side and then down the sail panel area and attaches to rear harness at the forward part of the trunk.
BTW: I had a "professional" install the last headliner in a 70 Charger last year for $150. And yes this was a professional at an upholstery shop. Not some hack. I would spend the money and have it done correctly. I've done about 10 E-body headliners myself including Two in OE builds and I've now come to the realization that its money well spent to have a pro do it.
Issues with doing it yourself. -
Wrinkles in the material. (headliner comes boxed and will have creases and wrinkles) Impossible to get out without steaming.
Not getting the headliner streatched in all the correct places.
Not having access to the same glues used by the pros. Spray-can headliner glue sucks. I could go on.