My Atwood Hydro Flame 8531-II RV furnace comes on, lights and then the burner shuts off after 2 seconds. Gas pressure is good. Voltage is at 13.2vdc while fan is running. The Ignition control has 4 wires (red, yellow, black, and white) plus the high tension igniter lead. The black is labeled "sense" but I don't know what it would test at.