Firstly, let me say its not my car, its my brothers. i hate fords as a rule. its a 93 1.1 model and the temp gauge pegs itself to the top from the moment you turn the key (even if the engine isnt started). I replaced the temperature sensor, but no change, so must be a problem with the electrical connection.

Anybody know how to get to the point where the wires go? looks like they end up near the fusebox but i dont fancy diving in there unless i am sure they go there...

 

It sounds like there's a short to earth somewhere, just follow the wires back from the sensor and looked for them rubbing on stuff.

Just one point, did you replace the sensor with a single wire? There's two, the other with a big fancy connector is for the cooling fan....just a thought, I don't mean to undermine you

 

I replaced the two wire sensor right on the top radiator hose. Its definately this one because when i pulled it the temp gauge dropped to zero. As for following the wires back, i did and all is fine as far as i can see, the unfortunate thing is that that is not very far - the wiring goes through the firewall in the area that the fusebox is in the cabin.

 

I had the same prob with my Pug 206, garage changed the sensor but prob still occured. Ended up having to put a new instrument display in. It's weird driving a car thats gone from 31K to 0 in the space of a morning!