I believe you are refering to the "sail switch". Have you tried cleaning the mechanism, it could be just binding up. What kind of shape was the rubber gasket (collar) in? It's the part that required the recall.
I haven't dug into mine yet other than to check out the burner etc. I don't think this furnace was ever used. There is no rust on the plenum or dirt in the flue. Don't know if it was repaired under the recall. All I know is that I ran it for 6 hours and it didn't set off my alarm. It ran quietly and the burner shut down and fired up when the thermostat called for heat.
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