I have an Econ Coleman furnace model # 7680. The sensor code blinks 3 times, telling me that the centrifugal switch failed to close. When removed, and the leads left unconnected from the switch, the green light stays on , the combustion blower comes on, and the hot surface igniter begins glowing but goes out after about 25 seconds. Meanwhile the green light remains solid and repeats this sequence after a few moments. This does not seem to happen every time, some times the blower comes on then goes off without the igniter getting hot. When this happens, the sensor light blinks three times again.
I tried to bypass centrifugal switch by connecting the 2 leads together, (as a test) the light remained solid, combustion blower starts, but no igniter glow, and after about 50 seconds blower goes out and code light starts blinking twice, telling me the centrifugal switch Is stuck closed.
Is this still the centrifugal switch?

Is this switch on the venter motor?