I agree with Gerry My Atwood fan would run, no ignition. I had used 12volt to keep refer cool while traveling; I guess it was too much of a drain on the battery
. When starting my 4runner, the fan came on, and the igniter lit the fuel. Some times the fan comes on, no ignition, I move the thermostat higher and lower,where one can hear the change in switch(name ? ) turn on and off ) Fan is still on and igniter comes on, heater then will run ok. I bought a new thermostat on Amazon comes in white or brown.