Hi
My 09 tdci Mondeo MK4 has a strange temperature gauge issue.

Sometimes it will appear ok (it never goes past halfway) but most other times not really.

Usually it will warm up fairly slowly and only get up to halfway when at speed (60+), slowly dropping down to 1/4 or just below when encountering towns/traffic and driving at a lower speed, but occasionally it does spend most of the journey at halfway, but will never stay there.

The car drives without fault apart from this minor issue and both heater and aircon work fine - there seems to be no noticeable effect if I have heat/aircon on or not. It has relatively newish coolant (usually at the right level or thereabouts).

I guess it could be a trial and error job - possibly a faulty sensor/connection, thermostat (less likely) or the instrumnet panel itself. Any thoughts?

Thanks, semi-baffled.