I have a 1990ish Cal-x fun spa with an electric heater that does not come on. I checked for current between the terminals of the heater and I have none, but I do have continuity across the heater terminals. It appears that the heater relay is not kicking over. I have by-passed the pressure switch, the themostat and the limit switch and still no kick of the relay. I do have power going into the unit/box, as the pump works just fine. I checked for power to the relay itself, and found no power to the 2 "trigger" wires, but power going into the main leads. I have checked continuity through the wires to the circuit block and everything looks good. The only thing I have not tested (I don't have any kind of schematic) is the top control panel. I'm really not sure where to go at this point. I just don't know what is supposed to trigger the relay other that the t/stat, pressure switch, and the limit switch. I f anyone can shed some light on this, I would very greatful. Oh, the model # of the control box/unit is 14-L010CL. I can include pictures if needed.