Woke up this morning.. my thermostat(non-carrier) showed no digits... I asumed it was broken... replaced it with a no digital type(slider)... got no heat but cool air coming out of vents...
Went downstairs to inspect furnace... got a yellow blinking led... one short... three long...
Any ideas?

Look on the inside of furnace door/cover, should tell you what the code means,, we couldn`t help you anyway without a model number off the furnace so it can be looked up