The limit switch (Item 17 in the diagram referenced in post #29 above) is supposed to be closed normally, and opens only in an overheat situation. A quick check is to remove both wires from it, and measure its resistance. The resistance should be very close to zero. If it is very high, it is stuck opened. In this case, give it a couple short sharp bops with a screwdriver handle and see if it closes. That is known as BILL'S UNIVERSAL FIX.
If shorting across it didn't work, that means there are multiple failures. While possible, this seems unlikely, so while you have it shorted, re-check everything carefully, using all the advice about wait-timing above.
I see the empty red connector you mentioned - good eye. I think I see a blue wire, but a better photo of it would help. Are you thinking that the blue wire should be coming out of the empty red connector? Is the end of the blue wire actually not connected to anything, as if it were broken off? Is the end of it stripped, leaving a half inch of bare copper showing, as if it had pulled out of the red connector? Is it long enough to reach the red connector? Bear on mind that an empty crimp connector may be what is intended by the mfr, and does not necessarily indicate a problem. In this case, it could be part of the thermistor circuit that is not used in this furnace.
Bill
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