We replaced the thermostat(mechanical) with a digital to get the control we wanted.
The fan should run after the burner cycles off as a cool down for a few minutes.
Mud dubbers in the exhaust will cause it to shut down on high temp. Circuit board may be the wrong one.
Unless there was a battery and/or converter problem that shouldn't have anything to do with the heater working unless the failure was such you didn't have 12 VDC.
Axis 24.1 class A 500watts solar TS-45CC Trimetric
Very noisy generator :M
2016 Wrangler JK dinghy
โThey who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety.โ Benjamin Franklin