Heater blowing hot all time/Engine Warning Light

[andywakey]

Hi all and apologies if I am posting in the wrong place.

My daughter has just purchased her first car....Ford KA 1.3(not sure which engine as yet).

There are a couple of problems and I am wondering if they are linked or separate issues.

She loves the car and it seems to be running fine however,I noticed the heater is permanently supplying hot air despite the setting.

The engine warning light is on and gives a code pointing to a heat sensor.

I noticed there was no coolant in which I topped up and there doesn't appear to be any obvious leak.

There does not appear to be any oil contamination so I don't think its head gasket.

The cooling fan appears to kick in ok but there seems to be an overheating issue although there is no temp guage fitted to verify this.

Could the no coolant and constant hot air be linked and would a problem with the in car heater bring a warning light on ?

Some have mentioned the thermostat,some water pump,air lock,expansion cap etc etc.

Could someone point me in best direction or let me know if I need to give more details?

Ka is 2003 with 70000 on clock.

many thanks

Andy

[delboy]

best of luck getting it sorted