We'll give it a spin.....er tap-tap after dinner.

Tap Tap didn't work.

Yup, continuity on each side of the switch and when the switch is depressed we have a closed circuit.
Is there a weird chance this thing is going into lockout and we aren't properly unlocking it?

No problem. Give me a minute or two. I'll just hard wire across switch and insulate. BTW, there is a little peep hole in the panel and I can see the fault code light which is not flashing, completely dark. Code on board indicates that if light is NOT flashing, no problem so we have a fan running without flame and no code light flashes.

Been Googling for manual for control board and finall found one as PDF. Says to get out of lockout need to interrupt call for heat MORE than 1 second but LESS THAN 20 seconds, anything else diverts board into automatic lockout which is one hour. Manual says that when lockout is detected gas valve is deenergized and blower is energized at heat speed.
If Board suffers internal failure, light is continuously on. System lockout is indicated by one flash then a pause, power on is indicated by one flash at power up. If 24v is interrupted for at least one second, auto reset can occurr but may also have to reset flame rollout sensor.
I'm going to power everything back up, reduce the thermostat to under house temp and then call for heat, turn thermostat back down under house temp for more about 10 seconds and see what happens.

TOUCHDOWN!
Turned both 120v and 24v power back on with thermostat set over room temp; i.e., calling for heat. Furnace went immediately into full blower mode. Turned all power off, set thermostat at room temp and powered back up, then reduced thermostat to under room temp for about 10-15 seconds, turned thermostat way up over room temp and wowow! proper furnace cylcing. Ran fine all night.
I'm positive that we got into lockout mode and with all my fiddling around never unlocked the control board.
Wonder why they don't put lockout info on control board along with trouble code.............grrrr....

FUMBLE....unit stopped cycling around 1:30 this afternoon. Have spent the rest of the afternoon tracing wiring and circuits for continiuty.
What I found....sort of amazing...is that there is a defective male pin on the control board. Vibration apparently causes loss of continuity between the male pin and the board causing an intermittent flame out. Why this beast went 4 days after cleaning the flame sensor without skipping a beat beats the devil out of me.
Today's tip came when once again I couldn't get the beast to cycle and out of frustration tried my old mechanics trick....gently tapped the control board and immediately went into ignition cycle but after a few minutes flamed out after the circulation blower came on.
Started wiggling the board and wiggling caused the unit to begin cycling and if you held the 12 pin connector just right the unit would run extended minutes.
The down side....no control boards in Iowa until tomorrow morning.

Let me give it a try. I got a little piece of wood I can 'bend' around. From what I can see, the pin has broken free or cracked free from where it enters the board.
Don't you just love intermittent problems....test of your skill and patience..........
I worked my way through college in the early 1970's turning wrenches on autos. Never was happy just replacing parts to solve something...tried to out-think the problem.
You've been patient with me....I'll let you know how this comes out.

Gotta remove this &*^%$ board once again. We are getting on a first name basis....not always friendly.

Grrrr....can't seem to get it to bend just right. New board arrives in AM.

Never could get board warped to make consistent contact.
Should have new board in an hour or two.

Got the new board in Des Moines finally after lunch and stuck in the furnace and we haen't missed a lick since then even through 16" of snow and 60mph wind. Think the problem is solved.