Ford Fiesta Heater Problem

[Cloud 9]

Just wondering if someone can help with a heater problem on 2006 Zetec TDCI, with the heat control on it only pumps out cold air until speed gets to 60mph and then drops off again at lower speed, the temp gauge remains normal, any ideas ?


Thanks

[Cloud 9]

Many Thanks guys......... It was low on water, topped up now working fine.