Can anyone tell me location of T-sensor on Ford Focus 2.0 Zetec 16V DOHC?

Dear All
When I am driving there are no problems with the cooling but if I make a lot of stop and go ( to much traffic) the temperature arrow is going up and the fan is ON to late almost to the red area, I've change several Thermostats but still I have the same problem the Fan is ON to late and I think that the problem is in T-sensor and I am trying to locate the T sensor on my engine but I can't locate can somebody help me with it???
Ford Focus SE 2001 Zetec 16V DOHC
pls answer me on drzaevaleksandar@gmail.com