I think the switch would be down by the handbrake.

I have the RFTC* version on my focus, so I'm guessing when I say the general
difference between the two seems likely to be that one applies braking to
one or both spinning wheels as necessary to reduce the wheelspin whereas the
other cuts engine power (to both wheels).

I drove a Mondeo with the TCS version a couple of years ago and it was quite
aggressive in cutting power. Maybe the brake version is less obtrusive? I'm
sure someone here will have driven both types and may wish comment further?

* right foot traction control - it's bloody useless ;-)