radiator fan wont kick on
 

hi all, i have a 1990 mustang 2.3. problem is the fan for the radiator wont kick on, overheats alot. someone told me i needed to get a new temperature coolant sensor. ok, i did, problem is i cant find where it goes. i was told its right under the intake manifold on the passenger side. cant find anything that resembles it. any help would be great. and also, is that truely my problem why the fan wont kick on? could it be as simple as the thermostat? i have heat. dont know.i attatched a pic of the general area where i was told it should be. thanks, mike