which sensor is at fault

[iffy]

My fan is not switching on and causing the car to overheat. After doing some digging around, one of the temp sensors is out of action, just do not know which one. When I switch on the AC, my fan comes on so that pretty much points to a sensor I suppose.

[Dean1309]

Hi, 

Funny you should post this, I've had the exact same problem Friday night and have just fixed the car yesterday. 

If the fan is not coming on, pull the connector off the coolant temperature switch which is located at the bottom drivers side of the of the radiator. To prevent over heating as a quick fix get a small piece of wire and strip the ends. Then insert the wire into both pins on the connector, switch the ignition on and the fans will come alive. If they come on then the switch is faulty. £10 from motor factors store. 

This was not my only problem, I by passed the switch but my car still over heated, I also replaced the thermostat as this was also £12. 

The main problem was my radiator as I refilled the radiator after replacing the thermostat I noticed water pouring from the bottom, so I had to replace the rad as well.