I have a Heat N Glo SL-750TR-D Propane fireplace produced around 2004. I am having an ongoing issue where the fan will not turn on when the fireplace gets up to temp. Eventually the fireplace shuts down on its own after approx. 10 minutes; I assume because it gets too hot. I've replaced the thermopile thinking that is a common issue, but that didn't change anything. I've replaced the temp sensor switch, but still can't get the fan to turn on. I've changed nothing else, and it used to work fine. So I know everything is hooked up correctly. I've unplugged the fan from the Junction Box and plugged it directly into an outlet, and the fan works fine. The Junction box also has power so I doubt its that. My next thought is the wiring or the Rheostat. Both seem fine though. Wiring seems perfectly okay. Rheostat acts normally but it could be that, I'm not sure. Any help would be appreciated!! Thanks!