04 focus temp gauge fault

[steve6304]

I have a 04 focus 1.4 petrol, the temp gauge reads in the normal position even when the engine has not been started. when i start the engine the gauge rises at the normal rate, i.e. it climbs halfway up the scale, in this case it reaches the red sector at normal temp, thermostat open and running o.k, but the cooling fan has been running at top speed almost constantly since the engine started.
I have checked the coolant temp with the gauge on the red, it is normal, around 90 deg. I have fitted a new sensor in the head but no change.
is it dash clocks or wiring ? help please
Forgot to mention that it is also a pig to start when cold, o.k when warm/hot.

Edited by steve6304 on Sunday 27th January 16:15