Another '40 wiring question.

[russcc]

The '40 has what maybe retrofitted turn signals. The switch is on the column, and it appears like when the rewired it, they wired them into 2 filament bulb sockets in the headlight & taillight areas. The front ones are straightforward, but the rear ones look like they run the turn signal through the stoplight circuit, so you have the stoplight filament doing double duty. Anyone have a diagram of how that might be wired up. ? Thank you Fordbarners.