I have a lennox 80mgf central heating and ac unit.. this morning when I woke up it wasn't blowing out any air through the floor vents.I messed with and found that the furnace was lighting and the blower was working through the exhaust fan. The led indicator light was indicating that everything was fine but the main fan wasn't working and the burners would kick off after 30 to 60 seconds. I checked the exhaust vent and it was clear so I took it apart so I could get to the main fan and it was moving freely so I put it all back together except the exhaust flute.. turned the power on and got my tester out to check for a bad relay or something and the next thing I know all is well. Put the flute back togeter and still worked fine.. any ideas as to what I should look for so my four kids don't have to wake up to a 59 degree house any more??

If it is still working it might have been a loose connection or a safety switch on the blower door. By taking it apart you moved something around so now it makes contact.