how can I fix my ford ka heater allways blowing hot?

not thermostat it is most likely the valve that lets water through to your heater inside car stuck open its in bonnet just follow pipes behind engine to bulkhead and you will find it (looks like water heater electric valve with wires connected test by turning heating in car to cold and feel pipe going in car to feel if getting hot should stay cold ) do it when car cold uf course

peesian
April 2010