My carrier furnace model 58sxc100-jg does not blow heat. The motherboard red light blinks 3 times fast, then 3 times slow. The fan does not go off even when set on auto. Any clue? The filter is clean.

Hi... I had the same problem... there is a tiny red reset button... about the size of a pen tip... it had to be pushed to reset the furnace
Hope this helps