[VetteVet]

Well you're still at it huh. Here is what I would do.
Disconnect the steering column wiring harness and put a new fuse in the stop turn holder in the fuse panel.
get a jumper wire about six inches long.
Turn the key on so you have power on the purple wire.
Jump between each of the turn signal wires both front and back and the purple wire.
See which one blows the fuse and that will tell you which one is shorted to ground.
If all the bulbs light and the fuse doesn't blow, then the short is in the turn signal harness or the switch itself.