Our heater controller has packed up, settings 1-4. However the aircon light works from 1 -3 but we have no air coming through the vents

Over the weekend we looked at the brushes which were ok and cleaned the parts and put it all back together as described in the factsheet - still not working. However this am I have slide the cold and hot slider to hot and you can feel a slight warm coming though but not through the controller speeds - does anyone have any ideas as up to 2 weeks ago the heater and aircon were working lovely.
