My heat will not go on when I have it on Auto on. When I put it on fan on it will work but then the fan runs all day.

It could be a loose wiring connection at the thermastat or the thermastat is faulty put the fan in auto and take a voltage reading from red to green if there is no voltage then it is closed and working properly. You could also take a spare piece of wire and jumper the two terminals if it starts replace thermastat.