I can take out fuse in furnace and then put back in and turn down to 55 degrees and blower still will run non stop . Its 22 years old and a train brand furnace.I took off cover on thromstate and blowed out all dust. But I notiest that they never put a filter in furnace for 3 years,and ran it without one all the time. How can I get blower to stop running all the time?

Most stats have a small fan switch karked AUTO and ON, which way is this stat set?

Locate the fan control. If cover is not installed, it will resemble a dial with numbers and a semi-circular slot. Tap on the dial. If you hear a "click" and the fan stops, replace the control.