I tried to turn the furnace on for the first time of the year last night. It will not kick on. If I turn the fan on it will blow. We have had the air on all summer without a problem. Am I missing a switch on the furnace to turn it on?
Any info will help.
Thank you.

What type of furnace do you have? Gas?. Heat Pump?. how to tell?

If you have high natural gas bills during the winter (like I do), we'll assume a gas furnace. There shouldn't be a special switch to enable the furnace. Make sure the gas valve is open (http://i.ehow.com/images/GlobalPhoto/Articles/5227821/gasshutoffvalve_Full.jpg) (the handle would be up in this photo). Remove the access panel (http://images.clipartof.com/small/24711-Clipart-Illustration-Of-A-Furnace-And-Water-Heater-In-A-Residential-Home-The-Cover-Off-Of-The-Furnace.jpg) to the furnace and stay by it while you have someone turn the thermostat to call for heat. Now, look for something like this hot surface ignitor (http://www.townlinx.com/rentals/tenants/images/HSI.jpg) to begin to glow. Actually, maybe locate this before asking for heat, just so you know where to look. (Most likely, it will be pointed away from you--into the furnace). It should glow, then you should hear the gas valve open with a click. If it doesn't glow, I would suspect the HSI (which is fairly easy to replace for anyone handy).

Best of luck.
WallyH

This may be too silly to bother with but are you sure you moved the switch all the way from AC to heat and not just in the middle?