The furnace seems to turn it self off at night like its on a timer for energy saving but I don't have any timer on it and then it turns back on in the morning. I have it set at 79 and at night it falls down to 70ish then goes back up in the monring.

What kind of thermostat do you have, programmable or non-programable.

mygirlsdad77, maybe its one of those day-night tstats, works during the day and sleeps at night

Well, we all got to sleep sometime, right?

Non-programable thermostat and it just started this year and the furnace is 7 years old.

Sorry I can't be of more help. I would have to see the furnace fail to test which component is causing it to shut down. Are you getting any blinking lights on the control board when its shut down at night? Really need to know exactly what is happening to assist further.

Im not getting any blinking lights and now the furnace comes on and off at night. The thermostat is a sears brand and its basic plain thermostat. Know I turn the thermnostat up to 80+ and it kicks in and out at night.

Okay, I would suggest starting with a new thermostat. Not to awefull expensive and may be the fix. I would suggest getting a Honeywell stat. Really can't go wrong with a Honeywell. If your looking for a basic stat, look into the T87, or Pro 5000 stats by Honeywell. Make sure that the stat you choose is compatible with your system. Good luck and please let me know how things work out.

Thank yo, I will try to get one this week and see if that works.

OK I installed a honeywell programmable thermostat rth2300b and I'm still getting nothing. The fan comes on when I turn it to the fan.

Thank you for the advise and the furnace is working great now that I have installed the thermostat.