how can i get hotpoint aquarius to heat water up?

hello hotpoint man im having trouble with my hotpoint aquarius, its not cleaning clothes properly ,on highest setting with whites its not getting hot .Im a scubber dryer engineer and think im up to any job on this machine if you could point me in the right way.Ive already tested heater ellements and thermostats,but i think these are for dryer .cheers Ian..