I am looking for some help diagnosing a problem with the gas furnace in my home. The blower continues to run continuously even after I have turned the thermostat to off. If I remove the covers and tap the control and limit switches with a screwdriver, the blower will turn off. I have it narrowed down to a couple of switches, but need help in diagnosing the correct one. The Lower Limit Switch and the Fan control switch. I know the fan control switch would make more sense, but when I tapped the Lower Limit Switch with the screwdriver, the blower shut off. Is it possible for the LLS to cause this, or am I looking in the wrong area all together? The thermostat is almost new and all the wires are tight and look like they are in good shape.

Hope someone can help,
Thanks,
Larry

.... http://www.hometips.com/home_probsol...ps_heat10.html

FBD.

.... http://www.inspect-ny.com/heat/FanLimitSwitch.htm

FBD