Yes, it's the rheostat. It's unfortunate that the cord is so short because it controls on/off and blower speed, but it's probably intentionally designed like that to keep people from laying it on top of the stove and melting the components. The big help is learning that the thermostat isn't in the controller. It's a little funny when I think about all the effort I made to warm up the control box! Anyway, I'm optimistic that I have a much better place to start rectifying this now. Thanks again.