I have the problems with the high speed  fan staying on and not timing out on cooling. The ecu was replaced at horrendous expense last July. The problem returned in November, disconnected battery, and it was ok the following day. However after a motorway run it has happened again. Battery disconnection unsuccesful. I read about the underbonnet fan relay problems but have been unable to remove the cover. Is it easier to access after removal of the battery or engine plastic cover?  in my attempts I must have dislodged the stuck contact and the fan is no longer starting when re-connecting the battery. The key will again work, however I am getting a flashing on & off of the warning lights when I turn the key to ignition. Any advice please? I would like to get in to the box to replace the 70 amp relay. 

Although the fan hadn't run on very long , I thought I had better check the battery status this morning. No load was just 12v, so time to try a big lithium powerbank, and it has started, thank goodness. I still need to replace the relay. Having compared similar size diesels, is the original battery for the 1.6 at 65 amp hours rather small?

That's moderately beefy, ample for the job.  The petrol fusions have only a 40A job from the factory.

Thanks for the info. At 7 years I guess it would be best to replace soon, but seem to recall all my previous diesels had larger batteries. I note some suppliers list 74 ah to fit so may go for that.

The metal battery securing strap also supports the relay box, so when the 2 nuts holding the strap are removed the top can easily  be detached revealing 3 relays. The grey one controls the fan, and mine had heavy burn out marks on the inside plastic casing and the make & break copper contaacts. The bulletin advised removing the old 70 amp relay coded 5MT5T 14B192 EA and replacing with the current F80B14B192AA one finis no 3968349. The Ford dealer that charged me £2000 to replace my ecu failure failed to find the faulty relay (£26) that caused the radiator fan to run on exhausting the battery