Suburban Red Yellow Blue wires

[Ryeandwater]

Pulled the bedroom N16 out to bench test.
When in the bus, thermostat turned up, fan would come on, approx 15 seconds after igniter would attempt to light burner. But no flame.
Tested and there is gas getting to the furnace, so suspect sail switch.
Removed the furnace and the wiring plug has three wires. Red is 12 volt positive, yellow is 12 volt negative, blue is thermostat. But there is only one blue wire in the plug? How do I make the furnace call for heat when on the bench?
Thanks.

[Bill Pape]

burners, heat exchanger, igniter need cleaning, tie the two positives together,

blow up a balloon and put it on the gas input, it will deflate, when calling for propane.
that way keeps the hair on your head and won’t go boom.

[Ryeandwater]

Tie blue and red together?

[Ryeandwater]

Figured it out.
Gas valve was not opening. Stuck solenoid, got it moving, exercised it multiple times, now working as it should. Making heat on the bench.
Will clean everything that I can and put it back in the bus.
Now onto the galley furnace, the living room works fine.