Epstine was right, first replace the cheapest most logical thing, that is missing. If it doesn't work right when the system is fully operational, then you can diagnose from there. Asking us what is wrong with it is like trying to figure out why your radio won't work when you don't have any speakers hooked up. If its not the thermostat, check the airflow of the E-fan (and get some decent name brand fans, the cheap ones suck).