Two y/o Suburban NT 34 furnace no fire

[Eagle & Bear]

Installed a new furnace two years ago. Ran it in late September. It worked great. In mid-October the fan would turn on but there was no fire. Turned the thermostat on. Fan runs for a minute then shuts down. Turned thermostat on again. Fan works but no fire. Nada Turned it on again. Nada. And again, zilch and again - only cold air.

Fan would run for a minute and then turn off. No click from gas valve. No sound from igniter. Battery is at 13.4V

Replaced gas regulator and pig tails. Burners and oven both work but furnace would not light.

Pulled furnace out from under the sink. Ordered a new board from Dinosaur and bought a new sail switch. While waiting for the board, I removed the old sail switch.

There are two small stainless machine screws with hex heads and a very small nut holding the sail switch on the housing in a very small space. The hex heads on the machine screw are beyond little. Not sure what the size of the hex head might be but it is smaller than the 4mm socket I have. It might be 2mm, 2.5mm or 3mm. Since I cannot find a socket I cannot determine the size of the hex head.

Got the sail switch off using an unconventional tool. Switch is comprised of a small rectangular plastic body with a thin 3" aluminum arm that extends into the furnace. The original arm has a small (1/2"X1/2") square piece of aluminum soldered to the far end of the arm.

The new sail switch looks like the old sail switch but the new one does not have the small square piece of aluminum soldered to the far end of the arm.

1: Any idea where I can get a socket small enough to put the sail switch back on? Or; where I can get another screw with a phillips head? Or; is there another solution?

2: Should I solder the small square piece of aluminum onto the far end of the new sail switch arm before I install it?

[pontzdav]

I was able to revive my Saul switch with a spray of contact cleaner and working it by hand (removed). I also found a replacement here

Hydro Flame Corp 31093 Sail Switch Kit Sm https://www.amazon.com/dp/B01N0L36VY..._obyPFbG72TBY0

[Eagle & Bear]

The screws that attached the sail switch are very small and have a very small hex head. Any tips on how to install the new one?

[Eagle & Bear]

Got the sail switch attached. Just re-purposed some of my tools. I just wanted to share the outcome. Started with the gas regulator and pigtails. No fire. Spent several hours of bench time to see if there was anything that could keep the furnace from igniting. Put about $400 worth of parts and two new propane tanks (the 43 year old welding had cracks), test the sail switch and high temp cutout switch and hope that the Dinosaur board was not defective. Took the furnace to a local RV repair shop and had them do a bench test. The furnace started every time that they hooked it up. Got home and reinstalled it. Screwed, glued, taped and got it ready to fire up. The furnace started up the first time and has been working since. The tank that was providing propane to our trailer ran out the night before the furnace stopped working. Conclusion: The yellow propane flex tubing had an air bubble in it. Even though I gained several new skills I hope that I never have to do this again.