over heating peugot 306 1.4?

my peugeot 306 2000 model 1,4cc petrol overheating i hav changed temp sensor and thermostat and bled system now the fan dosnt come on car temp gos up to 110 degs and fan dusnt come on if i put heating on full the temp gauge drops a bit if i hot wire the tem sensor switch the fan comes on ??? the peugeot garage gave me a new fan sensor box but i cant find where it is on the car!!! they said NSFwing by bumper but i cant see it there? please help tahnks