Original lighters were either Rochester or Casco depending on availability at the time of vehicle assembly. The center terminal that protrudes from the back of the socket is power into the socket. It can be either a 1/4" spade or #10 threaded pin. Both styles connect to B+ through push-on terminals. The lighter is grounded through the stamped steel tubular shroud (nut) that threads onto the back of the socket and retains it to the tilt-down ashtray. Typically, not always, the nut has a 1/4" spade terminal for a ground wire connection. Often, the sockets were not grounded from the factory via the ground terminal, and instead relied on a ground connection through the tray hinges. If you are experiencing a ground problem with a lighter that doesn't have the ground terminal on the nut, you can add a ground wire retained to the back of the tilt-down tray using a sheet metal screw.
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