Furnace just quit, light say combustion air switch stuck closed, can't get it to turn back on -35 outside at 1:30 am please someone give me idea how to fix it

You have to use a meter to check out anything on this furnace, but if the switch is bad then replace it. Check your relays and safeties with a meter. It really pays to learn to use a meter instead of relying on changing parts, and it's easier and cheaper, too. Here are some manuals: https://dl.dropboxusercontent.com/u/8010163/How%20to%20use%20Test%20Equipment%20Service%20Manu al.pdf
https://dl.dropboxusercontent.com/u/8010163/How%20to%20Diagnose%20and%20Fix%20Everything%20Ele ctronic.pdf
https://dl.dropboxusercontent.com/u/8010163/AC%20Wiring%20Diagrams.zip