Glad you got it sorted. I was confused by this though:
This old heater has signs of never being lit, it comes on OK but the fan does not come on.
I'm not sure why it would "come on" if the fan is not running. With my furnace (circa 1990) the fan turns on
first, and then the furnace lights up. After the thermostat shuts down the flame, the fan continues to run until the unit is cooled off.
There shouldn't be any fire burning unless the fan is running, as far as I know. That's why you have a sail switch - it should prevent the burner lighting off if there is no airflow through the furnace, to prevent it from overheating.
Steve
1990 Winnebago Warrior. "She may not look like much but she's got it where it counts!"