Spastruck

Some wise folk on here that may be able to help. I know it an old thread but maybe someone has this. I’ve one of these amc tubs. Display panel is fine but the temperature reading has gone mad and it’s not heating. Pump 3 all good but 1 and 2 dead. Pump one I hear a relay type click when selected. It happened after running all night. Is there a way to test the temp sensor or the heater? Not sure what to do with the pumps but if I could get the heater going be a win for Xmas.