Radiator Fan Not Turning On

Hi,

My Ford Fiesta 2006 16V 1.25 developed a coolant leak
recently. When it initially happened the warning sign came up on the display
and the temperature gauge was in the red. I stopped the car immediately and let
it cool down before driving it again after topping up with water. For the last couple of weeks I’ve got away
with topping up with water before each journey and the temperature remained
fine. I traced the leak to the thermostat housing and replaced it. Although the
leak has stopped I’ve noticed the fan doesn’t turn on which is probably why the
thermostat housing got the leak. I have tested the fan with a 12v direct feed
and it works ok. Also checked the fuses and wiring and can’t see any visible
problems. Should I replace the coolant sensor or maybe a relay? I did
disconnect it to see if it would turn on by default if there were no resistance
but it didn’t. Something else worth mentioning is that the air con doesn’t
work. When I turn it on the light comes on but there is no cold air and there
isn’t the usual sound of it clicking/clunking on.

Thanks, Paul