I assume you checked the motor was not faulty
have not seen these units to work on but looking at the parts I can get a feel to how they work
since this unit is no more than a fan heater in a draw then I would expect the fan to run continuously and the element to cycle on and off to control temperature. from what I can see there are 2 relays on the control board and I am assuming one controls the fan and the other controls the element
have you traced the wires back to the board and checked if the relay is working. ?
Dave