When I set the tempture up to 80 degrees on the thermometer and turn to auto the heat does not switch on? Our pilot light is lite and when I turn the heat on it only cool air comes out. Any ideas?
Thanks for the help!

Well,, its blowing cold air,so we know you have power. How old is furnace? Does it have a induction motor? is there a circuit board on control board on it with a little light that's is on solid or blinking? you can jumper the red and white wires on thermostat which bypasses the stat and tell if it will work without the thermostat,, If all works well ,replace the stat, tell us more after you check this much out