woodchopper is exactly right, the ka is fitted with the same heater control valve as the fiesta. It costs around �40 from ford or �10 from a breakers (if you can find a breakers with any left !) It takes half an hour max (dead easy) but you must ensure the serial number begins with the same four figures 96fw or 98fu - otherwise your car will overheat, the number is printed on the valve body, wich is located near the wiper motor at the centre of the bulkhead onder the bonnet.