Hi mu furnace for my AC goes on but I have no air coming out of the vents I also have a steady red light on the mother board .

My furnace will not click on consistently. It does come on sometimes and heats the house, but we can not get it to run most of the time. I changed the batteries in the thermostat, but it didn't matter. When I put it on fan, it kicks on right away if you go under the current room temperature. The red light in furnace flashes four times for ground wire.