Where are the transponder wires for 2000 ford windstar?

Question

And why do they change colors at connectors (for the four pin connector I suspect is it), and which ones should I use for my remote start transponder bypass (needing  rx and tx data and a ground and an ignition).

Answer 1

Rx - Gray / Orange

Tx - White / Green

The 4-Pin connector is located at the ignition switch, so you will have to remove the plastic around the steering column.

You can grab the ignition at the same spot you took it for the remote starter. And ground can be taken at the same spot as the remote starter also.