Radiator Fan

It's not supposed to come on when the gauge is in the middle, only when it reaches the upper end of the 'normal' zone. Not surprised it's not coming on at the moment as air temperatures are still pretty cool most of the time and passive cooling of the radiator is sufficient. You should try the diesels, we're all struggling to get the engine warm enough!

True SRH990...but my engine never reads more than the middle of the gauge.

I'm convinced the temp gauge only tells me what it thinks I want to know.
Never rises beyond the half way mark. If I'm crawling in traffic I will hear the fan cycle on and off, but the gauge never budges while this is happening...
(As an aside, I now think I've a coolant leak, approx 300ml/month, which only came to my notice when I realised the fan was cycling more than usual - and on a cold day, too)

You're correct - the gauge is driven by algorithm, not by the sensor. Its job could just as easily be done by a light, but customers like gauges. It rises to the middle roughly based on temperature, but then only goes higher if something is wrong.

If you want to know details, pop up the CHT readout on the cluster diagnostics.

Thanks for confirming my suspicions. I will probably do as you suggest the next time I'm into traffic. And yes, customers, myself included, do like gauges, but what's the point if it's not going to be meaningful? The truth shall set you free and all that...

You don't need to know the normal fluctuations of engine temperature. When there's a problem, it'll show you.

The point is purely to keep customers happy with the appearance, whilst not generating waste-of-time service false alarms and dissatisfaction through customers not understanding that temperature cycling is normal.

The previous model Fiesta ditched the gauge but Mondeo customers wouldn't, in general, like lights.

Well then whats the problem when it comes on just after 3 mins of driving the car from cold?

A/C on? Dodgy stat? Bring up the CHT reading on the cluster and see at what temperature it's turning on. It shouldn't come on below about 100°C unless you have the A/C on.

just noticed in the last few days the rad fan is coming on just after starting the car and not hearing it go off at all.