Atwood Furnace Lockout

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Problem solved. Checked ignition system, gap a little wide, adjusted per specs. Checked sail switch, working. Checked limit switch, 12v all around. Replaced control board with DINOSAUR, voila. Lit first time. Thanks for all the assistance. Know a lot more about the furnace operations than I did when I started.

I would suggest picking up some electrical grease from your local hardware store. Apply some to the multi-wire connector.

Thanks. I have Dinosaur board being shipped to house. Will check electrode this weekend. May go ahead and install new board anyway.

It is fairly easy.
In manual under burner head, electrode and valve assembly gives some information. Page 25 of previously posted manual
1) Turn off LP
2) Open outside access
3) disconnect LP line
4) look on right side of the gas valve, you should see two 1/4 headed sheat metal screws. Remove them. Easiest with 1/4 inch socket on 6 inch extention.
5) assembly should be loose and come out.
Harder to get back in as the screws are hard to reach with fingers. I use a piece of tape to hold screw in socket. Make sure it comes out with socket(tape)

How difficult is it to pull furnace to get to electrode(I do have outside access panel)? I never hear anything that sounds like the burner coming on.

Red wire from connector is for the gas valve. That sounds correct.
Blue wire is receiving command from thermostat. That is correct.
White wire is receiving command from thermostat. That is correct.
I would still clean the elctrode/ flame sensor. Inspect high voltage wire. Have helper turn on furnace as you listen carefully to see if clicking is in ignitor area or in high voltage lead indicating bad lead.
Do you hear any burner coming on?
Could be dirty orifice in gas piping?
Look at your water heater circuit board and compare it to the furnace circuit board. Some are the same. You could switch it out to test to see if that corrects problem.
Does your furnace have the exterior door for access?

When we had the same problem, we cleaned the igniter and the area the spark jumps to , made sure igniter was aligned properly (it wasn't) had to move it in a bit and then furnace worked properly again.

Ok,with everybody's help I'm making progress. With furnace off, white wire has 0v, blue wire has 12v, red wire has 0v. With furnace running(and I do smell gas), white wire has 12v, blue wire has 12v, and red wire has 12v when it tries to ignite. Red wire loses voltage within 5 - 10 seconds, and repeats this each time it tries to light. Electrode maybe? Board maybe? What's next?

Haven't done any of the checks enblethen suggested. I have removed and reseated the terminal from the ignition probe. won't have a chance to check anything until this weekend.