My furnace "forgets" to start when house temp. drops bellow the thermostat settings. It's a Bryant gas furnace installed in 2000 (builders grade). I have go in the basement and turn off the switch and then back on again and the blower kicks in and furnace starts working fine, even for a couple of hours but then the same thing happens again. It started about 1 month ago and it only happened about 6 times with the exception of the last few days when we constantly have to manually turn off and back on the switch. It works fine until the temp. reaches the thermostats settings, and then again it won't start when temp. drops, except manually. Please help.

I'm constantly running in the basement when it gets cold (I live in Michigan) to manually turn on switch. If it's something I can fix myself I sure could save some $. Thank you!