Traction assist started appearing around 1991/1992 as an option. After around 1997 or so, it became standard on most and eventually all TC's. I don't think you can disable trac-control in certain earlier models, according to some members of my former Crown Vic forum. But some of them told me that Ford sold a permanent disable kit for $7.
Depending on your year, the traction control disable switch may be located in the glove box. But you must disable it everytime you start the car, which is a PITA. I relocated mine in my Crown Vic to an easier location to disable or enable as I needed. Today, Ford finally got it right on newer vehicles and relocated the switch to a more desireable and easy to push area on the dash.
Some people have installed rocker switches to keep the Trac off unless they want it on. You can also short the wires together to disable it.
The traction control in the TC can be a pain in the snow, but useful in the rain or ice. I had to disable mine for dry road and snow, especially on an incline; the trac would put the car in neutral everytime I pressed the gas and the tires spun. Same thing in the sand...
