What is the path for a wire from the front side marker - turn signal to the trunk tail light?

[techzelle]

For the front side marker, you can remove the tire and wheel well liner to access the side marker wires from the back.
It's easier in the trunk, as you can just remove the trunk liner to access wiring.

But where / how does the wire go from front to back? under the door sill?

 

[terranx]

But where / how does the wire go from front to back? under the door sill?

Never checked on a Tesla in particular, but that's usually how it's done. EPC render makes it seem that's still the case with Teslas

 

[android04]

For the front side marker, you can remove the tire and wheel well liner to access the side marker wires from the back.
It's easier in the trunk, as you can just remove the trunk liner to access wiring.

But where / how does the wire go from front to back? under the door sill?

I would recommend getting a tool like this one Amazon.com to help you insert wires through rubber grommets. Then pass the wires through the grommet in the firewall below the cabin air intake into the passenger side footwell. Then you can tuck the wires below the bottom trim along the doors to the rear. Remove the rear seat bolster and run the wire into the trunk area. I've done it a few times on my car.