63' Dome Light and Gas Tank questions

[ABX131]

We made a lot of progress on the 63' this summer. It is now a drivable truck and my son and I are loving it. Question about the dome light. How does it turn on? There are no door pins to trigger it. Does it turn on by turning the headlight switch? Also regarding the fuel tank, It has been repainted and has some kind of padding under the tie down straps. Do the straps act as a ground to the mounts? If so then the paint and/or padding could be preventing a solid ground? When I turn on the key, the guage goes off the right end past the "F" and does not giv an accurate reading.