My outside temperature sensor on my peugeot 207 does not work

I have changed my coolant temp sensor but my 207cc still reads hot so im going to need to change the thermostat housing

Look on google images for 207 thermo switch and see if you recognise something. Its most often in the thermostat housing.

part supplied says a spanner
undo the wire connector
undo the sensor
fit the new sensor
fit wore connector
if coolant is lost refill cooling system to correct level

Tridon Coolant Temperature Sensor, TCS172
fits PEUGEOT 207 1.4 16V,1.6 16V

Normal to COLD?
You would only lose coolant if the engine was overheating - or, as you say - a leak.

It's probably a faulty temperature sending unit - these are common failures. You actually have nothing to worry about. The unit sends a signal from the engine to your temperature gauge in the car. Even if the unit is faulty the engine is still operating at the correct temperature - it's the signal to the temperature gauge that is wrong.

Your temperature sensor will look something like in the image below:
It's inexpensive and quick to rectify. A new sender unit can be fitted within minutes. Give a mobile mechanic a call ..

I read your question about the car heater.. No, the sensor wouldn't cause the heater to blow cold air. That fault is either air in the cooling system/heater system, or a blocked heater matrix.

Remove your radiator cap/coolant bottle cap. Open the heater controls to HOT and set on maximum. Start the engine and let it tick over - see if it forces any air out of the system when the heater should begin blowing hot.

If the heater still blows cold it may have a blocked matrix. Try a bottle of radiator/coolant system flush to see if that dislodges the blockage. The instructions will be on the bottle of coolant flush

Check the thermostat. It monitors the temperature of the coolant and turns the fan on to cool the engine when it detects the temperature is too high. When it goes faulty it can cause this issue of the fan being on all the time. (Better that it fails on than fails off and overheats the engine).

check each wheel behind see if no oil is seen,also in the brake fluid container.it can also leaking behind the mastercilinder whit you cannot see from outside.so be carefull,take the message seriously.

IT is an indication that the thermostat is held partially opened and allowing coolant circulation through the radiator resulting to cooler than normal engine operating temperatures . I would have it checked out at a radiator shop as the normal thermostat operating temperature is opening at around 80c and fully opened at 95 c

No need to sell the car if you get this problem, it is a common problem with the ECU and it can be repaired quite cheaply, as far as I can tell there is only one place that can repair this ECU at the moment - ecutesting.com. A full description of the symptoms for this fault can be found here: Peugeot 207 ECU Common fault

sound like engine coolant temperature sensor faulty also coolant level too low.

Abs esp is usually a triangle, it would have come on if a wheel was spinning or the car had lost road grip ie traction which is normal in low temperatures, which is why we drive different in low temp's to normal temp's....