Driving this morning (icy conditions) with the heating on full blast, accelerated at a roundabout and the car shuddered as though accelerator had not been pushed down enough (i wasn't driving but apparantly it was) as this happened the heating instantly died down and wouldn't resume full power for the rest of the drive. temp stayed normal although the fan in front of the radiator is a little loose (broken plastic clips) and wondered if this had anything to do with it? Am taking it to a garage this afternoon but wondered if anyone had any ideas as to what it could be? Car is a Fiesta style climate 1.2 about 6 years old very good condition. Apologes for lack of technical knowledge!